Voltage nb. Overclocking AMD processors with a locked multiplier: the THG guide

MSI P35 Diamond motherboard is a high-end model based on Intel P35 platform, which not only contains the latest hardware, but also has overclocking potential. Everyone knows that the BIOS is the soul of the motherboard, which determines its functionality and performance.

Below is the BIOS setup menu for the P35 Diamond motherboard. All functions related to performance, except for peripherals, system time, power management, are located in the "Cell Menu" section. Those wishing to adjust the frequency of the processor, memory or other devices (for example, the bus of the graphic card and the South Bridge) can use this menu.

Attention: Overclocking performance is dependent on environmental conditions, so we cannot guarantee that the following settings will work on every motherboard.

Remember, if you are not familiar with BIOS setup, it is recommended that you use the "Load Optimized Defaults" option to quickly complete the setup and ensure the system is working properly. Before overclocking, we recommend that users first boot the system with "Load Optimized Defaults", and only then fine-tune.

Cell Menu section of P35 Diamond motherboard

All overclocking settings are located in the "Cell Menu" section. They include:

D.O.T. control (dynamic acceleration technology control)

Intel EIST (Enhanced Intel SpeedStep® Technology)

Adjust CPU FSB Frequency

CPU Ratio CMOS Setting

Advanced DRAM Configuration

FSB / Memory Ratio

PCIEx4 Speed Controller

Adjust PCIE Frequency

Auto Disable DIMM / PCI Frequency

CPU Voltage

Memory Voltage

VTT FSB Voltage

NB Voltage

SB I / O Power (South Bridge I / O Power)

SB Core Power

Spread Spectrum

The user interface of the "Cell Menu" section is very simple and groups similar functions into groups; users can compare similar functions and adjust settings step by step.

Before starting overclocking, set the "D.O.T. Control" and "Intel EIST" functions to Disabled (default is enabled). These functions should be disabled in order to set custom processor and system bus voltages. After making these settings, the "CPU Ratio CMOS Setting" option will appear.

Adjust CPU FSB Frequency:
After loading the optimized settings, this function will automatically detect and display the CPU frequency. For example, for Intel Core 2 Duo E6850 processor, the value "333 (MHz)" will be displayed here. Frequency tuning can be done with the numeric keys or the Page Up and Page Down keys. During adjustment, the value shown in gray "Adjusted CPU Frequency" will change according to the set frequency.

CPU Ratio CMOS Setting:
Depending on the rated frequency of the processor used, for example 1333MHz, 1066MHz and 800MHz, the range of multipliers will be different. Usually the frequency is lowered to a minimum, which improves stability and ensures overclocking success.

Advanced DRAM Configuration:
This item is for setting the delays in the memory working cycle. The lower the corresponding value, the higher the speed. However, the limit depends on the quality of the memory modules used.

Advice:
If you are using commercially available overclocked memory modules, we recommend going to Cell Menu> Advanced DRAM Configuration> Configure DRAM Timing by SPD, set the latter to Disable. ... Next, there are 9 additional items that will enable users to achieve better memory performance.

FSB / Memory Ratio:
This setting determines the relationship between FSB and memory frequencies. If it is set to "Auto", the memory frequency will be equal to the processor FSB frequency. If it is user-defined, follow rule 1: 1.25. For example, a 1333MHz processor with DDR2-800 memory, then 1333MHz / 4 x 1.25 x 2 = 833MHz. DDR2 memory frequency will be 833MHz.

Advice:
To meet the wishes of overclocking enthusiasts, MSI has created a special Power User mode in the Cell Menu. Just press "F4" and a hidden menu will appear. The "Power User mode" menu items are memory oriented and include the SCOMP and ODT values.

Adjust PCIE Frequency:
Usually the PCI Express bus frequency has no direct relation to overclocking; however, fine-tuning it will also help overclocking. (The default setting is 100, it is not recommended to increase it beyond 120, this may damage the graphics card.)

CPU Voltage:
This point is critical for overclocking, however, due to the complexity of the relationships, it is not easy to find the best setting. We recommend that users adjust this value with caution, as improper installation can damage the processor. According to our experience, with a good fan, there is no need to set the CPU supply voltage limit. For example, for Intel Core 2 Duo E6850 processor, it is recommended to set the voltage in the range of 1.45 ~ 1.5V.

Advice:
The P35 Diamond motherboard uses DDR3 memory modules. According to JEDEC's definition of DDR3, its frequency range is between 800 and 1600MHz. The default values are 800, 1066, 1333 and 1600MHz. Therefore, when installing some special DDR3 modules, we recommend that you set the minimum FSB / memory frequency ratio, and fine-tune the memory supply voltage to achieve success.

VTT FSB Voltage:
To ensure similar supply voltages for all main devices, the VTT FSB voltage must also be increased. The increase should not be large, so as not to cause a negative effect.

NB Voltage:
Northbridge plays a decisive role in overclocking as it is important for maintaining the stability of the processor, memory and graphics card. This is achieved by increasing its supply voltage. We recommend that users fine-tune this setting.

SB I / O Power (South Bridge I / O Power):
The southbridge manages the connection of peripherals and expansion cards, which have recently played an increasingly important role on the Intel platform. The ICH9R's standard supply voltage is 1.5V, which determines the voltage setting for the I / O devices. We recommend raising the voltage to 1.7 ~ 1.8V, which will increase the stability of the joint operation of the North and South Bridges, and also help overclocking.

SB Core Power:
Previously, during overclocking, the South Bridge was ignored, but as the supply voltage rises, it increases performance.

In addition, remember that MSI in the voltage settings highlights different values in different colors: gray corresponds to the standard value, white means a safe value, and a dangerous one is highlighted in red.

Advice:
MSI warns you to check your fan speed and temperature frequently. Good cooling plays a decisive role in overclocking.

Attention:
The P35 Diamond is a powerful overclocking motherboard that provides full overclocking and system protection. In case of three unsuccessful overclocks in a row, the system will automatically set the default BIOS settings to reliably boot the system. Before overclocking, make sure each of the components is able to withstand its mode. MSI will not be held liable for any damage caused by unsuccessful overclocking. This article is for informational purposes only.

Once all the parameters are set, we recommend saving them using the "User Settings" function in the BIOS menu, which makes it easier to load the settings, and also allows you to restore the default settings in case of unsuccessful overclocking. The user can save two sets of settings and select the desired one.

Under User Settings "Press Enter" to save BIOS settings.

If the overclocking fails, users are left with the option to enter the User Setting section to set more appropriate parameters to restore normal operation.

How to Overclock P35 Diamond Motherboard

Sooner than expected, the Intel platform entered the era of DDR3 memory. DDR3 memory has lower operating voltage, heat dissipation and higher clock speed. It has better overclocking efficiency than DDR2. However, the chipset and memory modules still lack an overclocking environment and this limits the potential of DDR3.

MSI's MSI P35 Diamond comes with DDR3 memory and looks very similar to the P35 Platinum. It has more potential than its predecessor. The P35 Diamond motherboard can support Intel 1333MHz multi-core processors and use 1066MHz DDR3 memory modules with outstanding performance ().

When overclocked, the P35 Diamond has the same excellent performance as the P35 Platinum, but with a few differences. Thanks to DDR3 memory, users have the ability to fine-tune certain components, such as supply voltage and frequency ratios, which will affect overclocking results. In conclusion, we will dwell in more detail on the subtleties that should be borne in mind when starting overclocking.

Advice:
Overclocking increases the supply voltage of the main devices, and they generate more heat than usual. Therefore, cooling becomes an important issue during overclocking.

Attention:
OC is a software environment that any computer user comes into contact with every day. The stability of the OS determines the performance of the system. We recommend that users set the default settings during OS installation and do not enable any overclocking or optimizing features.

We used an Intel Core 2 Duo E6850 processor with the P35 Diamond motherboard. Memory modules provided by Corsair CM3X1024-1066C7 DDR3-1066, Nvidia GeForce 8600GTS graphics card, Western Digital WD740ADFD hard drive.

Memory modules Corsair CM3X1024-1066C7 DDR3-1066 / 7-7-7-21 / 1024MB / 1.5V

DDR3 memory has lower operating voltage, heat dissipation and higher clock speed for better overclocking performance. When installing memory modules, it is important to adjust the supply voltage.

BIOS default setting:

Window view of the program for determining the system parameters (CPU-Z 1.40):

The next step is to enter the "Cell Menu" section in the BIOS. Next, we set the frequency to 450MHz, the frequency multiplier is 8, which guarantees stability. According to the P35 chipset specification, increasing the CPU frequency also changes the memory frequency. Therefore, to achieve stability, we change the FSB / memory frequency ratio by 1: 1.

The following image shows the operating parameters we measured (depending on the environment)

After finishing the settings, you can press "F10" to save the parameters and click "OK" to restart the system with the new parameters.

Overclocking usually focuses on increasing the frequency of the processor, which reduces stability, but remains a widely used method. The following shows the performance gains achieved by overclocking.

According to the results, the performance improvement is about 5% and the system is very stable. Of course, users can define settings for their environment through a step-by-step selection.

Of course, our readers know all about overclocking. In fact, many reviews of processors and graphics cards would not be comprehensive enough without considering overclocking potential.

If you consider yourself an enthusiast, forgive us some basic information - we'll get to the technical details soon.

What is overclocking? At its core, the term is used to describe a component that operates at higher speeds than its specifications in order to increase performance. You can overclock a variety of computer components, including the processor, memory, and video card. And the level of overclocking can be completely different, from a simple increase in performance for inexpensive components to an increase in performance to an exorbitant level, normally unattainable for products sold in retail.

In this guide, we will focus on overclocking modern AMD processors to get the most out of your cooling solution.

Choosing the right components

The level of overclocking success is highly dependent on the system components. To begin with, you need a processor with good overclocking potential, capable of operating at higher frequencies than the manufacturer normally specifies. AMD today sells several processors that have reasonably good overclocking potential, with the "Black Edition" line of processors directly targeting enthusiasts and overclockers due to the unlocked multiplier. We tested four processors from different families of the company to illustrate the overclocking process for each of them.

For overclocking a processor, it is important that other components are also matched with this task in mind. The choice of a motherboard with an overclocking friendly BIOS is quite critical.

We took a pair of Asus M3A78-T (790GX + 750SB) motherboards, which not only provide a fairly large set of functions in the BIOS, including support for Advanced Clock Calibration (ACC), but also work perfectly with the AMD OverDrive utility, which is important for squeezing the maximum out of Phenom processors.

Choosing the right memory is also important if you want to achieve maximum performance after overclocking. Whenever possible, we recommend installing high-performance DDR2 memory that is capable of operating at frequencies above 1066 MHz on AM2 + motherboards with 45- or 65-nm Phenom processors that support DDR2-1066.

During overclocking, frequencies and voltages increase, which leads to an increase in heat generation. Therefore, it is better if your system runs a proprietary power supply that provides stable voltage levels and sufficient current to cope with the increased requirements of an overclocked computer. A weak or outdated power supply, loaded to capacity, can ruin the overclocker's efforts.

Increasing frequencies, voltages and power consumption will, of course, lead to an increase in heat dissipation levels, so the cooling of the processor and case also affects the overclocking results a lot. We didn't want to reach any overclocking or performance records with this article, so we took rather modest coolers at the price of $ 20-25.

This guide is intended to help those users who are less experienced in overclocking processors so that they can enjoy the performance benefits of overclocking a Phenom II, Phenom, or Athlon X2. Let's hope that our tips will help novice overclockers in this difficult but interesting business.

Terminology

A variety of terms that often mean the same thing can confuse or even frighten the uninitiated user. Therefore, before we go directly to the step-by-step guide, we will look at the most common terms associated with overclocking.

Clock Frequencies

CPU frequency(CPU speed, CPU frequency, CPU clock speed): The frequency at which the computer's central processing unit (CPU) executes instructions (for example, 3000 MHz or 3.0 GHz). It is this frequency that we are planning to increase in order to gain performance gain.

HyperTransport Channel Frequency: frequency of the interface between the CPU and the northbridge (for example, 1000, 1800 or 2000 MHz). Usually the frequency is equal to (but should not exceed) the frequency of the northbridge.

Northbridge frequency: frequency of the northbridge chip (for example, 1800 or 2000 MHz). For AM2 + processors, an increase in the northbridge frequency will lead to an increase in memory controller performance and L3 frequency. The frequency should not be lower than the HyperTransport channel, but it can be increased significantly higher.

Memory frequency(DRAM frequency and memory speed): The frequency, measured in megahertz (MHz), at which the memory bus operates. Both the physical frequency, such as 200, 333, 400 and 533 MHz, and the effective frequency, such as DDR2-400, DDR2-667, DDR2-800, or DDR2-1066, can be specified.

Base or reference frequency: By default, it is 200 MHz. As you can see from AM2 + processors, other frequencies are calculated from the base using multipliers and sometimes dividers.

Frequency calculation

Before we get into the description of calculating frequencies, it should be mentioned that most of our guide covers overclocking AM2 + processors such as Phenom II, Phenom or other Athlon 7xxx models based on the K10 core. But we also wanted to cover the early AM2 Athlon X2 processors based on the K8 core, such as the 4xxx, 5xxx and 6xxx lines. There are some differences between overclocking K8 processors, which we will mention below in our article.

Below are the basic formulas for calculating the frequencies of the AM2 + processors mentioned above.

CPU clock speed = base clock * CPU multiplier;
northbridge frequency = base frequency * northbridge multiplier;
HyperTransport channel frequency = base frequency * HyperTransport multiplier;
memory frequency = base frequency * memory multiplier.

If we want to overclock the processor (increase its clock frequency), then we need to either increase the base frequency or increase the CPU multiplier. Let's take an example: the Phenom II X4 940 processor runs at a base frequency of 200 MHz and a CPU multiplier of 15x, which gives a CPU clock speed of 3000 MHz (200 * 15 = 3000).

We can overclock this processor to 3300 MHz by increasing the multiplier to 16.5 (200 * 16.5 = 3300) or raising the base frequency to 220 (220 * 15 = 3300).

But it should be remembered that the other frequencies listed above also depend on the base frequency, so raising it to 220 MHz will also increase (overclock) the frequencies of the north bridge, HyperTransport channel, as well as the memory frequency. On the contrary, simply increasing the CPU multiplier will only increase the CPU clock speed of the AM2 + processors. Below we will look at a simple overclocking through a multiplier using the AMD OverDrive utility, and then go to the BIOS for a more complex overclocking through the base frequency.

Depending on the motherboard manufacturer, the BIOS options for the processor and northbridge frequencies sometimes use not just a multiplier, but the ratio of FID (Frequency ID) and DID (Divisor ID). In this case, the formulas will be as follows.

CPU clock speed = base clock * FID (multiplier) / DID (divisor);
northbridge frequency = base frequency * NB FID (multiplier) / NB DID (divisor).

Keeping the DID at level 1, you will go to the simple multiplier formula that we discussed above, that is, you can increase the CPU multipliers in increments of 0.5: 8.5, 9, 9.5, 10, etc. But if you set the DID to 2 or 4, you can increase the multiplier in smaller increments. To complicate matters, values can be specified as frequencies, such as 1800 MHz, or as multipliers, such as 9, and you may need to enter hexadecimal numbers. In any case, refer to your motherboard manual or look online for hex values for different CPU and Northbridge FIDs.

There are other exceptions, for example, you may not be able to set multipliers. So, the memory frequency in some cases is set directly in the BIOS: DDR2-400, DDR2-533, DDR2-800 or DDR2-1066 instead of choosing a memory multiplier or divider. In addition, the frequencies of the Northbridge and HyperTransport channel can also be set directly, and not through a multiplier. In general, we do not advise you to worry too much about such differences, but we recommend that you return to this part of the article if the need arises.

Test Hardware and BIOS Settings

Processors

AMD Phenom II X4 940 Black Edition (45nm, Quad-Core, Deneb, AM2 +)
AMD Phenom X4 9950 Black Edition (65nm, Quad-Core, Agena, AM2 +)
AMD Athlon X2 7750 Black Edition (65 nm, Dual-Core, Kuma, AM2 +)
AMD Athlon 64 X2 5400+ Black Edition (65 nm, Dual Core, Brisbane, AM2)

Memory

4 GB (2 * 2 GB) Patriot PC2-6400 (4-4-4-12)
4 GB (2 * 2 GB) G.Skill Pi Black PC2-6400 (4-4-4-12)

Video cards

AMD Radeon HD 4870 X2
AMD Radeon HD 4850

Cooler

Arctic Cooling Freezer 64 Pro
Xigmatek HDT-S963

Motherboard

Asus M3A78-T (790GX + 750SB)

Power Supply

Antec NeoPower 650W
Antec True Power Trio 650W

Useful utilities.

AMD OverDrive: Overclocking Utility
CPU-Z: System Information Utility;
Prime95: stability test;
Memtest86: memory test (bootable CD).

Hardware monitoring: Hardware Monitor, Core Temp, Asus Probe II, other utilities included with the motherboard.

Performance Testing: W Prime, Super Pi Mod, Cinebench, 3DMark 2006 CPU test, 3DMark Vantage CPU test

Manually adjust Memory Timings;
Windows Power Plan: High Performance.

Remember that you are exceeding the manufacturer's specifications. Overclocking is done at your own risk. Most hardware manufacturers, including AMD, do not provide a warranty for overclocking damage, even if you use AMD's utility. THG.ru or the author is not responsible for damage that may occur during overclocking.

Introducing AMD OverDrive

AMD OverDrive is a powerful all-in-one overclocking, monitoring and testing utility for AMD 700 series motherboards. Many overclockers do not like using the software utility under the operating system, so they prefer to change the values directly in the BIOS. I also usually avoid the utilities that come with motherboards. But after testing the latest versions of the AMD OverDrive utility on our systems, it became clear that the utility is quite valuable.

We'll start by looking at the AMD OverDrive utility menus, highlighting interesting features as well as unlocking advanced features we'll need. After starting the OverDrive utility, you are greeted with a warning message, clearly stating that you are using the utility at your own peril and risk.

When you agree, by pressing the "OK" button, you will be taken to the "Basic System Information" tab, which displays information about the CPU and memory.

The "Diagram" tab shows the chipset diagram. If you click on a component, then more detailed information about it will be displayed.

The "Status Monitor" tab is very useful during overclocking as it allows you to monitor the processor clock speed, multiplier, voltage, temperature and utilization level.

If you click on the Performance Control tab in Novice mode, you get a simple engine that allows you to change the PCI Express (PCIe) frequency.

To unlock advanced frequency settings, go to the "Preference / Settings" tab and select "Advanced Mode".

After selecting the "Advanced" mode, the "Novice" tab was replaced by the "Clock / Voltage" tab for overclocking.

The "Memory" tab displays a lot of information about the memory and allows you to adjust the delays.

There is even a built-in benchmark for quickly assessing performance and comparing it with previous values.

The utility also contains tests that stress the system in order to check the stability of the work.

The last tab "Auto Clock" allows you to perform automatic overclocking. It takes a lot of time, and all the excitement is lost, so we did not experiment with this function.

Now that you are familiar with AMD OverDrive and put it into Advanced mode, let's move on to overclocking.

Multiplier overclocking

With the 790GX motherboard and Black Edition processors we used, overclocking with AMD OverDrive is pretty easy. If your processor is not Black Edition, then you cannot raise the multiplier.

Let's take a look at the regular operating mode of our Phenom II X4 940 processor. The base frequency of the motherboard varies from 200.5 to 200.6 MHz for our system, which gives a core frequency between 3007 and 3008 MHz.

At the nominal clock speed, it is useful to conduct some performance tests in order to compare the results of an overclocked system with them (you can use the tests and utilities we suggested above). Performance tests allow you to evaluate the gain and loss in performance after changing settings.

To overclock the Black Edition processor, check the "Select All Cores" checkbox on the "Clock / Voltage" tab, then start increasing the CPU multiplier in small steps. By the way, if you do not check the box, then you can overclock the processor cores separately. As you overclock, remember to watch temperatures and conduct stability tests all the time. In addition, we recommend that you take notes regarding each change, where you will describe the results.

Since we expected a solid boost from our Deneb processor, we skipped the 15.5x multiplier and went straight to the 16x multiplier, which gave the CPU core frequency at 3200 MHz. With a base frequency of 200 MHz, each increase in the multiplier by 1 gives a clock speed increase of 200 MHz, and an increase in the multiplier by 0.5 - 100 MHz, respectively. We did stress tests after overclocking with the AOD stability test and the Small FFT Prime95 test.

After stress testing Prime 95 for 15 minutes without a single error, we decided to further raise the multiplier. Accordingly, the next multiplier of 16.5 gives a frequency of 3300 MHz. And at this core frequency, our Phenom II passed through stability tests without any problems.

A multiplier of 17 gives a clock speed of 3400 MHz, and again stability tests were performed without a single error.

At 3.5 GHz (17.5 * 200) we successfully passed a one-hour stability test under AOD, but after about eight minutes in the heavier Prime95 application we got a blue screen and the system rebooted. We were able to run all performance tests on these settings without crashing, but we still wanted our system to pass the 30-60 minute Prime95 benchmark without crashing. Therefore, the maximum overclocking level of our processor at the nominal voltage of 1.35 V is between 3.4 and 3.5 GHz. If you do not want to raise the tension, then you can stop there. Or you can try to find the maximum stable CPU clock at a given voltage by increasing the base clock in one megahertz steps, which for a multiplier of 17 will give 17 MHz at each step.

If you are not averse to raising the voltage, then it is better to do this with a small step of 0.025-0.05 V, while you need to monitor the temperatures. Our CPU temperatures remained low, and we started to raise the CPU voltage a little, while a slight increase to 1.375V led to the fact that Prime95 tests were performed at 3.5GHz quite stable.

For stable operation with a multiplier of 18 at a frequency of 3.6 GHz, a voltage of 1,400 V was required. To maintain stability at a frequency of 3.7 GHz, a voltage of 1.4875 V was required, which is more than the AOD allows you to set by default. Not every system will be able to provide sufficient cooling at this voltage. To increase the default AOD limit, edit the AOD parameters .xml file in Notepad to increase the limit to 1.55 V.

We had to raise the voltage to 1,500V to keep the system stable in the 3.8GHz tests with a multiplier of 18, but even raising it to 1.55V did not bring the Prime95 stress test stable. The core temperature during Prime95 tests was somewhere around 55 degrees Celsius, which means that we hardly needed better cooling.

We rolled back to 3.7GHz overclocking, with the Prime95 benchmark running for an hour successfully, meaning the stability of the system was checked. Then we started to increase the base frequency in 1 MHz steps, while the maximum overclocking level was 3765 MHz (203 * 18.5).

It is important to remember that the frequencies that can be obtained through overclocking, as well as the voltage values for this, change from one processor sample to another, so in your case everything may be different. It is important to increase the frequency and voltage values in small increments while performing stability tests and monitoring the temperature throughout the entire process. With these CPU models, increasing the voltage does not always help, and the processors may even lose stability if the voltage is increased too much. Sometimes, for better overclocking, it is enough just to strengthen the cooling system. For optimal results, we recommend keeping the CPU core temperature under load below 50 degrees Celsius.

Although we were unable to increase the processor frequency above 3765 MHz, there are still ways to further improve system performance. Raising the northbridge frequency, for example, can have a significant impact on application performance, as it increases the speed of the memory controller and L3 cache. The northbridge multiplier cannot be changed from the AOD utility, but it can be done in the BIOS.

The only way to increase the clock speed of the northbridge under AOD without rebooting is to experiment with the CPU clock speed with a low multiplier and a high base clock. However, this will increase both the HyperTransport speed and the memory frequency. We will take a closer look at this issue in our guide, but for now, let me give you the overclocking results of three other Black Edition processors.

The other two AM2 + processors overclock in exactly the same way as the Phenom II, with the exception of one more step - enabling Advanced Clock Calibration (ACC). ACC is only available on AMD SB750 Southbridge motherboards such as our ASUS 790GX chipset. ACC can be enabled in both AOD and BIOS, but both require a reboot.

For 45nm Phenom II processors, it is better to disable ACC, as AMD claims this feature is already present in the Phenom II die. But with 65nm K10 Phenom and Athlon processors, it is better to set ACC to Auto, + 2% or + 4%, which can increase the maximum achievable processor frequency.

Nominal frequencies.

Maximum multiplier

Maximum acceleration

The screenshots above show the overclocking of our Phenom X4 9950 at a nominal frequency of 2.6 GHz with a 13x multiplier and a processor voltage of 1.25 V. used for overclocking. The multiplier was increased to 15x for a 400 MHz overclock at nominal voltage. The voltage was increased to 1.45V, then we tried the ACC setting in Auto, + 2%, and + 4%, but Prime95 was only able to run for 12-15 minutes. Interestingly, with the ACC function in Auto mode, 16.5x multiplier and 1.425V, we were able to increase the base clock to 208MHz, resulting in higher stable overclocking.

Nominal frequencies

Maximum overclocking without increasing voltage

Maximum overclocking without using ACC

Maximum acceleration

Our Athlon X2 7750 runs at the nominal frequency of 2700 MHz and voltage of 1.325 V. Without increasing the voltage, we were able to increase the multiplier to 16x, which gave a stable 3200 MHz operating frequency. The system worked stably at 3300 MHz, when we slightly increased the voltage to 1.35 V. With the ACC function disabled, we increased the processor voltage to 1.45 V in 0.025 V increments, but the system was not able to work stably with the 17x multiplier. It crashed even before stress testing. Setting the ACC for all cores to + 2% allowed us to reach an hour of stable Prime95 operation at 1.425 V. The processor did not respond very well to voltage increases above 1.425 V, so we were able to get the maximum stable frequency of 3417 MHz.

The benefits of enabling ACC, as well as overclocking results in general, vary significantly from one processor to another. However, it's nice to get such an option at your disposal, and you can spend time fine-tuning the overclocking of each core. We didn’t get a big boost in overclocking from enabling ACC on both processors, but we still recommend reading the 790GX review, where we looked at ACC in more detail, and there this feature had a more serious impact on the overclocking potential of the Phenom X4 9850.

BIOS options

Our Asus M3A78-T motherboard has been flashed with the latest BIOS to support the newer CPUs and provide the best chance of overclocking.

First, you need to enter the motherboard BIOS (this is usually done by pressing the "Delete" key during the POST). Check your motherboard manual and see how you can clear the CMOS (usually with a jumper) if the system fails the POST. Remember that if this happens, then all previously made changes such as time / date, shutdown of the graphics core, boot order, etc. will be lost. If you are new to BIOS setup, then pay special attention to the changes you make and write down the original settings if you cannot remember them later.

Simply navigating through the BIOS menus is completely safe, so if you're new to overclocking then fear nothing. But make sure you exit the BIOS without saving your changes if you think you might accidentally screw something up. This is usually done with the "Esc" key or the appropriate menu option.

Let's dive into the BIOS of the Asus M3A78-T as an example. BIOS menus differ from one motherboard to another (and from one manufacturer to another), so use the instructions to find the appropriate options in your model's BIOS. Also, keep in mind that the options available are highly dependent on the motherboard model and chipset.

In the main menu (Main), you can set the time and date, connected drives are also displayed there. If the menu item has a blue triangle on the left, then you can go to the submenu. The "System Information" item, for example, allows you to view the BIOS version and date, processor brand, frequency and amount of installed RAM.

The "Advanced" menu consists of several nested submenus. The "CPU Configuration" item gives information about the processor and contains a number of options, some of which are better to be disabled for overclocking.

You will probably spend most of your time in the "Advanced" "JumperFree Configuration" menu item. Manual setting of important settings is provided by transferring the "AI Overclocking" item to the "Manual" mode. Other motherboards will likely have these options in a different menu.

We now have access to the necessary multipliers, which can be changed. Note that in BIOS, the CPU multiplier changes in 0.5 increments, and the Northbridge multiplier in increments of 1. And the HT channel frequency is indicated directly, not through a multiplier. These options differ significantly between different motherboards, for some models they can be set via FID and DID, as we mentioned above.

In the "DRAM Timing Configuration" item, you can set the memory frequency, be it DDR2-400, DDR2-533, DDR2-667, DDR2-800 or DDR2-1066, as shown in the photo. In this BIOS version, you do not need to set the memory multiplier / divider. In the "DRAM Timing Mode" item, you can set delays, both automatically and manually. Reducing latency can increase performance. However, if you do not have completely stable memory latency values at hand at different frequencies, then during overclocking it is very reasonable to increase the CL, tRDC, tRP, tRAS, tRC and CR delays. In addition, you can get higher memory frequencies if you increase the tRFC latency to very high values such as 127.5 or 135.

Later, all "relaxed" delays can be reverted back to squeeze out more performance. It is time consuming to reduce one latency per system startup, but it is worth spending to get the best performance while maintaining stability. When your memory will run out of specification, run a stability test with utilities such as the Memtest86 bootable CD, as unstable memory can lead to data corruption, which is undesirable. With all that said, it’s safe to give the motherboard the ability to adjust latencies on its own (usually with fairly "weakened" latencies) and focus on CPU overclocking.

Advanced overclocking

In this case, the adjective "extended" is not very appropriate, because, unlike the methods discussed above, we will present here overclocking via BIOS by increasing the base frequency. The success of such overclocking depends on how well the components of your system can overclock, and in order to find the capabilities of each of them, we will iterate over them one by one. In principle, no one forces you to follow all the steps given, but finding the maximum for each component can, in the end, give a higher overclocking, since you will understand why you are running into one or another limit.

As we said above, some overclockers prefer direct overclocking through the BIOS, while others use AOD to save time for testing, since they do not need to reboot every time. The settings can then be manually entered into the BIOS and tried to improve them even more. Basically, you can choose any method, as each has its own advantages and disadvantages.

Again, it would be nice to disable the Cool "n" Quiet and C1E power saving options in the BIOS, Spread Spectrum and automatic fan control systems that reduce the fan speed. We also turned off the "CPU Tweak" and "Virtualization" options for some of our tests, but did not find any noticeable effect on any of the processors. You can later enable these features if required, and you can check if they affect system performance or the stability of your overclocking.

Finding the maximum base clock speed

We now turn to the technique that owners of non-Black Edition processors will have to follow to overclock them (they cannot increase the multiplier). Our first step is to find the maximum base frequency (bus frequency) at which the processor and motherboard can operate. You will quickly notice all the confusion about the naming of the various frequencies and multipliers that we mentioned above. For example, the reference clock in AOD is named in CPU-Z as "Bus Speed" and "FSB / FSB Frequency" in this BIOS.

If you plan to overclock only through the BIOS, then you should lower the CPU multiplier, northbridge multiplier, HyperTransport multiplier and memory multiplier. In our BIOS, lowering the Northbridge multiplier automatically reduces the available HyperTransport link frequencies to or below the resulting Northbridge frequency. The CPU multiplier can be left as normal and then reduced in AOD, which makes it possible to further raise the CPU frequency without rebooting.

For our Phenom X4 9950 processor, we chose an 8x multiplier in the AOD utility, since even a 300 MHz base frequency with such a multiplier will be lower than the nominal CPU frequency. Then we raised the base frequency from 200 MHz to 220 MHz, and then increased it in 10 MHz steps up to 260 MHz. Then we went to a 5 MHz step and increased the frequency to a maximum of 290 MHz. In principle, it is hardly worth increasing this frequency to the stability limit, so we could easily stop at 275 MHz, since it is unlikely that the northbridge will be able to operate at such a high frequency. Since we were overclocking the base clock in AOD, we ran AOD stability tests for a few minutes to make sure the system was stable. If we were to do the same in BIOS, then simply booting under Windows would probably be a good enough test, and then we would run final stability tests at a high base frequency to be sure.

Finding the maximum CPU frequency

Since we already lowered the multiplier in AOD, we know the maximum CPU multiplier and now we already know the maximum base frequency that we can use. With the Black Edition processor, we can experiment with any combination within these limits to find the maximum value for other frequencies, such as the northbridge frequency, the HyperTransport channel frequency, and the memory frequency. For now, we'll continue our overclocking tests as if the CPU multiplier was locked at 13x. We'll be looking for the maximum CPU frequency by increasing the bus frequency by 5 MHz at a time.

Whether overclocking via BIOS or via AOD, we can always go back to the base frequency of 200 MHz and set the multiplier back to 13x, which will give the nominal clock speed of 2600 MHz. By the way, in this case, the multiplier of the north bridge will still remain 4, which gives a frequency of 800 MHz, the HyperTransport channel will operate at 800 MHz, and the memory - at 200 MHz (DDR2-400). We will follow the same procedure for raising the base frequency in small increments, performing stability tests each time. If necessary, we will increase the CPU voltage until we reach the maximum CPU frequency (connecting ACC in parallel).

Maximum performance gain

Having found the maximum CPU frequency of our AMD processors, we took a significant step towards increasing system performance. But the processor frequency is only part of the overclocking. To squeeze out the maximum performance, you can work on other frequencies. If you increase the voltage of the north bridge (NB VID in AMD OverDrive), then its frequency can be increased to 2400-2600 MHz and higher, while you will increase the speed of the memory controller and L3 cache. Increasing the frequency and decreasing RAM latency can also have a positive effect on performance. Even the high-performance DDR2-800 memory we used can be overclocked to above 1066 MHz by increasing the voltage and possibly reducing the latency. HyperTransport channel frequency usually does not affect performance above 2000 MHz and can easily lead to loss of stability, but it can also be overclocked. The PCIe frequency can also be slightly overclocked to around 110 MHz, which can also give a potential performance boost.

As all the mentioned frequencies rise slowly, stability and performance tests should be carried out. Adjusting various parameters is a lengthy process, perhaps beyond the scope of our guide. But overclocking is always fun, especially since you will get a significant performance boost.

Conclusion

Let's hope that all of our readers who want to overclock an AMD processor now have enough information on hand. Now you can start overclocking using AMD OverDrive utility or other methods. Remember that the results and the exact sequence of actions vary from one system to another, so you should not blindly copy our settings. Use this manual only as a guide to help you find the potential and limitations of your system on your own. Take your time, do not step up, monitor temperatures, perform stability tests, and increase the voltage slightly if necessary. Always carefully grope for the limit of safe overclocking, since a sudden increase in frequency and voltage blindly is not only the wrong approach for successful overclocking, but it can also damage your hardware.

The last tip: each motherboard model has its own characteristics, so it doesn't hurt to get acquainted with the experience of other owners of the same motherboard before overclocking. Advice from experienced users and enthusiasts who have tried this motherboard model in work will help to avoid pitfalls.

Addition

We tested one more copy of the AMD Phenom II X4 940 Black Edition processor, provided by the Russian representative of AMD. It worked successfully at 3.6GHz when we increased the supply voltage to 1.488V (CPUZ data). It looks like 3.6GHz is the threshold for most air-cooled processors. We successfully overclocked the memory controller to 2.2 GHz.

UEFI (Unified Extensible Firmware Interface)

BIOS chip

The firmware is located near the south bridge on the Winbond 25064FVA1G chip. All screenshots were taken in version 2.10.1208, brought back to normal by the Load optimized Defaults command.

The interface is almost the same as in the solutions of competitors - AMI is AMI. However, there are more opportunities, according to the status of the product.

Upon entering the BIOS, we are presented with the Extreme Tweaker tab, leaving no doubt for whom this product is intended.

At the bottom of the ET is an impressive list of voltages available for change. The adjustment ranges are wide, and when the Extreme OV option is activated, they become completely huge. A summary of the voltages is shown in the table below.

Voltage	Minimum value, V	Maximum value, V	Maximum value, V (Extreme OV)	Step
CPU Manual Voltage	0,675	1,75	2,3	0,0063
CPU / NB Manual Voltage	0,5	1,55	1,9	0,0063
CPU VDDA Voltage	2,2	2,8	3	0,0063
DRAM Voltage	0,86	1,85	2,135	0,005
NB Voltage	1,1	1,5125	2	0,0063
NB HT Voltage	1,2	1,5125	2	0,0063
NB 1.8V Voltage	1,8	2,0075	3,0078	0,0133
SB Voltage	1,1	1,6033	1,802	0,0133
VDDR	1,205	1,5105	1,802	0,0133

DRAM Timing Control

The DRAM Timing Control subsection allows you to control the memory delays.

DRAM Driving Control

In case you have installed a lot of RAM and the system is not stable enough, you can try to increase the multipliers in the DRAM Driving Control section.

The GPU.DIMM Post subsection allows you to see the status of memory modules and video cards before booting the system (for example, whether they warmed up after LN2).

DIGI + Power Control

DIGI + Power Control contains everything that will help you fine-tune the digital power supply system of the board.

As usual, the Main section allows you to set the time, select the preferred language and set a password to access the settings.

Almost all operations for controlling the components integrated into the board are available in the Advanced section. It makes no sense to examine them in detail, the screenshots speak for themselves.

CPU Configuration

North Bridge \ Memory Configuration

SATA Configuration

SATA Configuration \ SB SATA Configuration

USB Configuration

CPU Core On / Off Function

Onboard Devices Configuration

Onboard Devices Configuration \ SB HD Azalia Configuration

iROG Configuration

The Monitor subsection allows you to monitor the current state of the system. There is no summary screen, everything is divided into categories. In addition, the section for setting the operating mode of the cooling system was brought here.

Temperature Monitor

Fan Speed Monitor

Fan Speed Control

In the Boot section, you can traditionally change the priorities of disks at boot and see a list of available drives.

ASUS EZ Flash 2 Utility

Initially, an attempt was made to update the firmware using the BIOS Flashback, which, as stated, does not even require an installed processor and memory. After completing the steps listed in the instructions, the BIOS_FLSHBK LED near the BIOS chip turned on, and we began to wait. After ten minutes, nothing had changed, so it was decided to restart the system. The terrible thing did not happen, the firmware did not deteriorate. There is no miracle - the BIOS version remains the same. But the built-in utility for updating the BIOS coped with its task perfectly.

The result of the MyLogo2 utility

By the way, when updating the BIOS from under Windows, it is possible to replace the startup image. This feature is called MyLogo. The aspect ratio of the picture, judging by the preview in the utility, should be approximately a multiple of 160: 97. The 1280x776 picture required a reduction of up to 98% and ended up being compressed to the standard 5: 4. The requirements for the image could be mentioned in the program or instructions, but no one was puzzled by this for the sake of an entertainment function.

ASUS SPD Information

In the ASUS OC Profile section, you can save and load profiles for different operating modes. Eight slots should be sufficient for most reconfiguration needs.

In the GO Button File subsection, you can specify the system parameters that will be applied when the GO Button is pressed. It is very convenient for an open stand, not very good in all other cases.

BIOS in Simplified EZ Mode

In simplified mode, it is convenient to view summary information. In addition, it will be easier for the younger generation of users to work with BIOS: the setting is similar to working with a utility under Windows.

Shortcuts menu. Not translated into Russian

⇡ Overclocking and stability

System overclocking can be done from the UEFI BIOS, from the operating system using AI Suite II, and even from another computer using ROG Connect technology. The first two methods have been discussed many times, so they are not of interest, and the last one is a unique overclocking opportunity. The first thing that comes to mind is changing the CPU frequency right during subtests, for example, in the 3DMark package. Not fair? Why is that? This is a standard feature of the board.

It looks like this: a corresponding feature is activated in the BIOS, a button is pressed on the back of the motherboard, a complete cable is plugged into the closest (white) USB port to it. The other computer installs the ROG Connect client software, plugs in the other end of the cable ... and here it is, access to all voltages, frequencies and temperatures! Sometimes there were failures: the client module did not show the frequencies at which the CPU and the board worked. When any of the parameters was changed, everything returned to normal (the Refresh button did not lead to such an effect).

Not everyone needs such features, but still such cards are rarely bought by those who do not need advanced functionality. If such an opportunity did occur, a software and hardware tandem will come to the rescue: AI Suite II and TPU. Available "fast" and "extreme" overclocking.

The first one raised the base frequency by 3 MHz and raised the memory frequency to 815 (1630) MHz. According to the system, this is equivalent to a 2% increase. They did not check it.

"Extreme" overclocking lasted a little longer and included stability tests.

The screenshots above show the main system parameters before and after activating this function.

Nevertheless, the utility provides a lot of possibilities for fine tuning and monitoring. You can evaluate them by clicking on the screenshot of interest. Of greatest interest is the control of the Digi + II power system: you can instantly change not only the voltages, but also the phase operation parameters or the intensity of voltage holding under load (Load-Line Calibration).

The maximum bus frequency was 359 MHz, but this is obviously the processor's limit. By the way, this motherboard reached a memory frequency of 1948 MHz, which at the time of publication is the second highest in the world according to HWBOT.

Let's see how the motherboard power system behaves under overclocking conditions. To do this, we will alternately check the voltages at idle and under load at different modes of Load-Line Calibration. The measurement results for the Phenom II X6 1100T Black Edition processor at 4111 MHz are shown in the table below. During testing, the voltages were set to 1.5 / 1.25 / 1.57V for Vcore / CPU_NB / DRAM respectively. AIDA64 (soft) will be used as a program for measurements, and a Victor 86D (hard) multimeter was used to measure the actual voltage. IDLE and LOAD markings indicate idle and full load conditions using OCCT 4.3.1. There are only three available modes for CPU / NB, so there are dashes in the table. BSOD in brackets - not instantaneous, there was enough time to measure. Column FullAuto denotes the choice of voltage and LLC level by the motherboard itself.

Method	Voltage	FullAuto	Auto	Regular	Medium	High	Ultra High	Extreme
soft (IDLE)	Cpu	1,356	1,512	1,464	1,476	1,488	1,488	1,512
hard (IDLE)		1,367	1,522	1,485	1,494	1,502	1,511	1,522
soft (BURN)		BSOD	1,56	1,404	1,428	1,476	1,512	1,548
hard (BURN)		BSOD	1,551	1.415 (BSOD)	1,464 (BSOD)	1,485	1,524	1,569
soft (IDLE)	CPU / NB	1,168	1,263	1,257	-	1,263	-	1,263
hard (IDLE)		1,171	1,273	1,269	-	1,272	-	1,273
soft (BURN)		BSOD	1,296	1,27	-	1,27	-	1,277
hard (BURN)		BSOD	1,298	1,285	-	1,29	-	1,296

Based on the results obtained, the High mode turns out to be the most suitable, since it does not overestimate the voltage (although it allows a slight drawdown under load).

The RAM power supply system was deprived of such an opportunity, leaving only the phase control (Optimal / Extreme) and the choice of the PWM frequency:

Method	Voltage	FullAuto	Optimal	Extreme
soft (IDLE)	DRAM	1,647	1,568	1,568
hard (IDLE)		1,663	1,583	1,583
soft (BURN)		1,654	1,568	1,568
hard (BURN)		1,665	1,584	1,584

As you can see, when using two RAM strips, there is no difference between them. The real voltage is slightly overestimated relative to that set in the BIOS.

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Auto overclocking options

Some motherboards have special parameters for complex overclocking of the system, allowing you to increase its performance without going into the subtleties of configuring individual components. This method is available for novice users, but its effectiveness may be low, and in some cases the system may even be unstable.

Dynamic Overclocking (D.O.T.)

With this parameter, you can use the dynamic overclocking technology, which is used in a number of MSI motherboards. The system monitors the load on the processor, and when it reaches the maximum, its performance will be increased, and after the load drops, the processor will automatically return to normal mode.

Possible values:

□ Private, Sergeant, Captain, Colonel, General, Commander - choosing one of the specified values will set the processor acceleration level from 1% (for Private) to 15% (for Commander).

Some MSI motherboards allow advanced dynamic overclocking settings. The Dynamic Overclocking Mode parameter allows you to select components for overclocking, and using the CPU D.0.T3 step 1/2/3 setting and PCIE D.0.T3 step 1/2/3 setting you can adjust the overclocking levels for the processor and PCI bus Express.

CPU Intelligent Accelerator 2 (C.I.A. 2)

C.I.A. 2 is a dynamic overclocking technology similar to D.O.T., but used in Gigabyte motherboards.

Possible values:

□ Disabled - dynamic overclocking technology is not used;

□ Cruise, Sports, Racing, Turbo, Full Thrust - selecting one of these values sets the processor acceleration level from 5% (Cruise) to 19% (Full Thrust).

Memory Performance Enhance (Performance Enhance)

This parameter allows you to increase the performance of RAM in motherboards from Gigabyte and some other manufacturers.

Possible values:

□ Standard (Normal) - RAM overclocking is not used;

□ Fast, Turbo, Extreme - select one of the overclocking levels. The effect of these values may vary depending on the motherboard model.

AI Overclocking (Al Tuning)

This parameter, which is available on some ASUS motherboards, allows you to select one of the available overclocking options. Possible values:

□ Manual - all overclocking parameters can be changed manually;

□ Auto - optimal parameters are set;

□ Standard - standard parameters are loaded;

□ AI Overclock (Overclock Profile) - the system will be overclocked by the amount set using the Overclock Options parameter (possible options are from 3 to 10%);

□ AI N.O.S. (Non-Delay Overclocking System) - uses dynamic overclocking technology similar to D.O.T. Configurable in more detail using the N.O.S. Option; depending on the board model, you can set the overclocking level as a percentage or the sensitivity of the dynamic overclocking system.

AI Overclock Tuner

This parameter is used to select the overclocking mode in a number of new motherboards from ASUS.

Possible values:

□ Auto - automatic adjustment of parameters (default mode);

□ H.M.R. - tuning memory operation in accordance with the Intel Extreme Memory Profile (X.M.P.) standard. This standard must also be supported by the memory modules, and the extreme Memory Profile is used to select the current memory profile;

□ D.O.C.P. - when this value is selected, you can set the desired operating mode of the RAM using the additional parameter DRAM OS. Profile, and the base frequency (BCLK) and multiplication factors for memory and processor will be automatically matched;

□ Manual - all overclocking parameters are manually configured.

Robust Graphics Booster (LinkBoost)

This parameter allows you to speed up the video system by increasing the clock frequencies of the video adapter.

Possible values:

□ Auto - the video system operates normally at the default clock frequencies;

□ Fast, Turbo - the video system operates at higher frequencies, due to which the performance is slightly increased (especially in Turbo mode).

Intel Turbo Boost

This parameter allows you to enable dynamic overclocking technology for processors of the Intel Core i7 / 5 family. Intel Turbo Boost Technology automatically increases the frequency of the processor when one or more cores are loaded and the processor is not overheating. Possible values:

□ Enabled - Turbo Boost technology is enabled. When all the cores are loaded, the processor multiplier can be automatically increased by 1–2 steps, which corresponds to an increase in the clock frequency by 133 or 266 MHz. If only one core is loaded, the processor frequency can be increased by two steps or more, depending on the processor model;

□ Disabled - Turbo Boost is disabled.

CPU overclocking options

As you know, each processor operates at a certain frequency, which is indicated in its technical characteristics and is defined as the product of the base frequency and the multiplication factor.

CPU Clock Ratio (CPU Ratio Selection, Multiplier Factor, Ratio CMOS Setting)

The parameter sets the multiplication factor for the central processor. Most modern processors only allow decreasing it or not reacting at all to changing the ratio. However, there are models with unlocked multipliers in the range of manufacturers (for example, the Black Edition from AMD), which can be easily overclocked by simply increasing the multiplier. Possible values:

□ Auto - the multiplication factor is set automatically depending on the processor;

□ 7.0X, 7.5X, 8.0X, 8.5X, 9.0X, 9.5X, etc. - by choosing one of the indicated values, you can force the processor to work with a special multiplication factor, as a result of which its clock frequency will differ from the rated one.

CPU Host Clock Control (CPU Operating Speed)

The parameter enables manual control of the FSB frequency (BCLK) and the multiplication factor, which may be needed during overclocking. Possible values:

□ Disabled or Auto Detect - the processor clock frequency is set automatically; this value should be selected for system operation in normal, non-overclocked mode;

□ Enabled (On) or User Define - the processor clock frequency can be changed manually using the CPU FSB Clock parameter (this value is used during overclocking).

CPU FSB Clock (CPU Host Frequency (MHz), FSB Frequency, External Clock)

This parameter sets the frequency of the system bus FSB, or the external frequency of the central processor, with which all other frequencies are synchronized. Changing the FSB frequency is the main way to overclock processors, and the range and step of adjustment depends on the chipset and motherboard model.

If you are not going to overclock your computer, set this parameter to Auto, or disable manual tuning for the processor operating mode using the CPU Operating Speed parameter or similar.

BCLK Frequency (Base Clock)

This parameter is used in systems based on Core i3 / 5/7 processors and allows you to change the base frequency, which affects the operating frequencies of the processor, QPI bus, RAM and its controller. The nominal value of the base frequency is 133 MHz, and the step and adjustment range depend on the board model. To access this parameter, you may need to enable manual frequency tuning using the Base Clock Control parameter or similar.

QPI Frequency (QPI Link Speed)

This parameter allows you to set the frequency of the QPI bus, which is used to connect the Core i3 / 5/7 processor with the chipset.

Possible values:

□ Auto - QPI frequency is set automatically in accordance with the passport parameters of the processor;

□ хЗб, х44, х48 - multiplier that determines the QPI frequency relative to the base one (133 MHz);

□ 4800, 5866, 6400 - in some boards, instead of a multiplier, a numeric frequency value in megahertz can be used.

CPU / NB Frequency (Adjust CPU-NB Ratio)

This parameter allows you to set the frequency of the memory controller integrated into the AMD processor. Depending on the model of the board, the frequency in megahertz or a multiplier relative to the base frequency can be used as values.

CPU Voltage Control (CPU VCore Voltage)

Using this parameter, you can manually change the voltage of the CPU supply, which is sometimes necessary when overclocking. Possible values:

□ Auto (Normal) - processor supply voltage is set automatically in accordance with its passport parameters;

□ the numerical value of the voltage in the range from 0.85 to 1.75 V (depending on the model of the motherboard, the range and step of adjustment may be different).

In some motherboards, the CPU Over Voltage parameter is used for the same purposes, which allows you to increase the voltage relative to the rated voltage by a specified amount.

ATTENTION

Excessive supply voltage can damage the processor. For most modern processors, an increase in voltage of 0.2-0.3 V is acceptable.

Additional processor voltages

Modern processors, in addition to computing cores, can contain cache memory, a RAM controller, and other components. For them, some boards have the ability to adjust the supply voltage and signal levels, but their effect on the stability of an overclocked system is usually small. Here are some of these parameters:

□ CPU VTT Voltage - voltage of the QPI bus controller and L3 cache (Intel Core i3 / 5/7);

□ CPU PLL Voltage - supply voltage of the phase-locked loop. This parameter is relevant for Intel quad-core processors;

□ CPU / NB Voltage - voltage of the memory controller and L3 cache in AMD processors;

□ CPU Differential Amplitude (CPU Amplitude Control, CPU Clock Drive) - adjust the amplitude of the processor signals;

□ Load-Line Calibration - enabling this parameter will improve the stability of the supply voltage under a heavy load on the processor.

Advanced Clock Calibration (NVidia Core Calibration)

This parameter is intended to improve the overclocking potential of Phenom and Athlon processors. Advanced Clock Calibration (ACC) technology is supported in the new AMD processor chipsets to automatically adjust the operating frequency and voltage of the processor.

Possible values:

□ Disable - ACC technology is disabled, this value is recommended for the standard (non-overclocked) operating mode;

□ Auto - ACC technology works in automatic mode, this value is recommended for acceleration;

□ All Cores - when this value is selected, you can use the Value parameter to set the ACC level as a percentage for all cores at the same time;

□ Per Core - unlike the previous option, you can configure the ACC for each core separately. Manual ACC tuning may be necessary if the system is unstable when set to Auto.

This parameter aroused great interest among computer enthusiasts, as it allows unlocking inactive cores and transforming a dual- or triple-core Athlon / Phenom processor into a quad-core one. Read more about this below.

RAM overclocking options

The RAM works on control signals from the memory controller, which generates a sequence of signals with some delays in between. The delays are necessary for the memory module to have time to execute the current command and prepare for the next one. These delays are called timings and is usually measured in memory bus clock cycles. Among all the timings, the most important are the following: CAS # Latency (tCL), RAS # to CAS # delay (tRCD), RAS # Precharge (tRP) and Active to Precharge Delay (tRAS).

When the BIOS is configured by default, all the necessary memory parameters are set automatically. Each memory module has a special chip called SPD (Serial Presence Detect), which records the optimal values for a particular module. To overclock, you should disable automatic memory tuning and set all parameters manually, and when overclocking the processor, you will not have to increase the memory frequency, but, on the contrary, lower it.

The number of RAM parameters available for configuring can vary greatly for different models of motherboards, even those based on the same chipset. Most motherboards have the ability to change the memory frequency and main timings, which is quite enough for overclocking (Fig. 6.2). Fans of careful optimization and overclocking can choose a more expensive motherboard with many additional settings, and in the cheapest motherboards, manual memory tuning tools will be limited or absent altogether. RAM parameters can be found in the overclocking section, in the Advanced Chipset Features section, or in one of the subsections of the Advanced section.

Rice. 6.2. Basic parameters of RAM

DRAM Timing Selectable (Timing Mode)

This is the main parameter for adjusting the RAM, with which you can select manual or automatic mode of setting parameters.

Possible values:

□ By SPD (Auto) - parameters of memory modules are set automatically using data from the SPD chip; this is the default and should not be changed unless necessary;

□ Manual - parameters of memory modules are set manually; when this value is selected, you can change the settings for operating frequencies and timings.

Configure DRAM Timing by SPD (Memory Timing by SPD)

The meaning of these parameters is completely similar to the DRAM Timing Selectable discussed above, and the possible values will be as follows:

□ Enabled (On) - RAM parameters are set automatically in accordance with SPD data;

□ Disabled (Off) - the RAM is manually configured.

Memory Frequency (DRAM Frequency, Memclock Index Value, Max Memclock)

The parameter displays or sets the frequency of operation of the RAM. In most cases, this frequency is set automatically in accordance with the information from the SPD. By manually adjusting the frequency, you can make the memory speed up, but not every module will work stably.

Possible values:

□ Auto - the frequency of the RAM is set automatically in accordance with the SPD data (by default);

□ 100, 120, 133 (РС100, РС133) - possible values for SDRAM memory;

□ 200, 266, 333, 400, 533 (DDR266, DDR333, DDR400, DDR533) - possible values for DDR memory;

□ DDR2-400, DDR2-566, DDR2-667, DDR2-800, DDR2-889, DDR2-1067 - values for DDR2 memory;

□ DDR3-800, DDR3-1066, DDR2-1333, DDR2-1600 - values for DDR3 memory.

On some cards, this parameter is read-only, and the System Memory Multiplier parameter must be used to change the memory frequency.

System Memory Multiplier (FSB / Memory Ratio)

Determines the ratio (multiplier) between FSB frequency (BCLK) and memory frequency.

Possible values:

□ Auto - the relationship between FSB (BCLK) frequency and memory frequency is automatically adjusted according to the SPD data;

□ ratio (e.g. 1: 1, 1: 2, 3: 2, 5: 4) or multiplier (2, 2.5, 2.66, 3.00, 3.33, 4.00, etc.) ), defining the relationship between FSB frequency (BCLK) and memory frequency. The specific set of values depends on the chipset type and board model.

The manual setting of the multiplier is used during acceleration, in this case the multiplier (ratio) is lowered so that it does not go beyond the permissible limits when raising the base frequency. You can control the actual value of the memory frequency using the Memory Frequency information parameter or diagnostic utilities such as CPU-Z (www.cpuid.com) or EVEREST.

CAS # Latency (tCL, DRAM CAS # Latency)

This parameter sets the delay between the onset of the column sample signal (CAS #) and the start of data transfer.

Possible values of this parameter depend on the type of modules used and the model of the board. For DDR memory, the adjustment range can be from 1.5 to 3 clocks, for DDR2 - from 3 to 7 clocks, for DDR3 - from 4 to 15 clocks. Decreasing the CAS # Latency value will speed up the memory operation, but not all modules can work stably at low latencies.

RAS # to CAS # delay (tRCD, DRAM RAS-to-CAS Delay)

This parameter changes the delay time between the line sampled signal (RAS #) and the column sampled signal (CAS #).

The adjustment range depends on the board model and can be from 1 to 15 clock cycles. The lower the value, the faster the access to the cell, however, as in the case of CAS # Latency, too low values will lead to unstable memory.

RAS # Precharge (tRP, DRAM RAS # Precharge, SDRAM RAS # Precharge, Row Precharge Time)

The parameter sets the minimum allowed time to recharge the string after it is closed.

Possible values are from 1 to 15. At lower values, the memory works faster, but too low can lead to its instability.

Active to Precharge Delay (tRAS, DRAM RAS # Activate to Precharge, Min RAS # Active Time)

The parameter sets the minimum time between the line activation command and the close command, that is, the time during which the line can be opened.

The adjustment range depends on the board model and can be from 1 to 63 clocks. There is no unambiguous relationship between the value of this parameter and memory performance, therefore, tRAS should be selected experimentally for maximum effect.

DRAM Command Rate (1T / 2T Memory Timing)

The parameter sets the delay when transmitting commands from the controller to the memory.

Possible values:

□ 2T (2T Command) - the delay is equal to two clock cycles, which corresponds to a lower speed, but greater reliability of the memory;

□ IT (IT Command) - one clock cycle delay increases the speed of the RAM, but not every system can work normally.

In some BIOS versions, there is a 2T Command parameter, when enabled, a delay of two clock cycles is set, and when disabled, a delay is set in one clock cycle.

Extreme Memory Profile (H.M.R.)

This parameter allows you to enable support for extended memory profiles. This technology was developed by Intel and assumes writing additional sets of parameters to the SPD chip for operation at an increased frequency or with minimal delays. To use this technology, it must be supported by your memory module.

Possible values:

□ Disabled - the memory is operating normally;

□ Profile !, Profile2 - Selects one of the higher performance memory profiles. To find out the parameters of these profiles, refer to the detailed specification of your module.

Additional memory options

As noted, some motherboards have additional memory options. They have a smaller performance impact than the main timings discussed above, so in most cases they should be left at their default values. If you have the time and desire to experiment, you can use them to slightly increase the speed of memory. The most common parameters are:

□ tRRD (RAS to RAS delay) - delay between activation of rows of different banks;

□ tRC (Row Cycle Time) - the duration of the cycle of a row of memory;

□ tWR (Write Recovery Time) - delay between the end of the write operation and the start of precharge;

□ tWTR (Write to Read Delay) - the delay between the completion of the write operation and the beginning of the read operation;

□ tRTP (Precharge Time) - the interval between the read and precharge commands;

□ tRFC (ROW Refresh Cycle Time) - the minimum time between a row refresh command and an activation command or another refresh command;

□ Bank Interleave - defining the interleaving mode when accessing memory banks;

□ DRAM Burst Length - determination of the size of the data packet when reading from the RAM;

□ DDR Clock Skew (Clock Skew for Channel А / В) - adjusts the offset of clock signals for memory modules.

ATTENTION

Changing memory timings can lead to unstable operation of the computer, therefore, at the first failure, you should set the default timings.

DDR / DDR2 / DDR3 Voltage (DDR / DDR2 / DDR3 OverVoltage Control, Memory Voltage)

This parameter increases the supply voltage of the RAM chips for their more stable operation at higher frequencies. Selecting Auto (Default) will set the memory chips to the standard supply voltage, which is 2.5 V for DDR memory, 1.8 V for DDR2, and 1.5 V for DDR3.

For more efficient overclocking of RAM, you can slightly increase the supply voltage by choosing one of the suggested values. The range and step of adjustment depend on the board model, and both absolute and relative voltages can be used as values.

Some boards may have additional parameters for setting the reference voltages separately for each memory channel, for example, Ch-A / B Address / Data VRef. Almost always, they should be set to Auto, and their adjustment may be necessary only for extreme acceleration.

ATTENTION

To avoid irreversible damage to memory modules, do not set excessively high voltages, and also take care of more efficient cooling of the modules.

If you overclock the "Vishera" processor, you will get a set of different parameters in the UEFI / BIOS. Although, compared to the Intel platform, there are not many of them. Below we have listed the most important of them.

Voltages "Vishera"

CPU Voltage

CPU Core Voltage - differs from one CPU to another depending on the VID / quality of the processor. This is the tension that most overclockers should watch out for.

CPU-NB Voltage

Northbridge voltage in CPU (not to be confused with chipset voltage); this part of the CPU operates in its own frequency and voltage domain. The CPU-NB frequency determines the speed of the memory controller and L3 cache. The CPU-NB component has a significant impact on the overall system performance. At higher frequencies, it is recommended to raise the CPU-NB voltage to improve system stability.

CPU Voltage Offset

Most motherboards allow a bias voltage to be set to increase the voltage above the CPU VID voltage range. The offset voltage is added to the VID value and can affect overclocking both positively and negatively. The actual voltage is calculated as follows: CPU Voltage + Offset. Example: VID 1.350 V + offset 0.100 V = 1.45 V actual voltage.

NB Voltage

Chipset voltage. When overclocking by increasing the multiplier, you do not need to increase it.

HT Voltage

If you want to overclock the AMD processor also via the HT interface, then you may need to increase this voltage.

V DDQ

Memory voltage. Depends on the memory sticks used.

LLC / Loadline Calibration:

Prevents Vdroop effect (voltage drop under load). Unfortunately, this setting is not found on every AMD motherboard.