27. 06.2018

Dmitry Vassiyarov's blog.

What is the difference between the server room RAM from the usual - is there a difference?

Good day, my dear readers and I am glad to communicate with you again. Today's topic cannot be called popular, because no matter how it relates to ordinary computers. But in fact, the question of how server RAM differs from ordinary RAM has become increasingly of concern to ordinary users.

I would link this with unsuccessful attempts upgrade based on the logical assumption that hardware for equipment operating around the clock will be of better quality and more reliable.

But in fact, the server hardware is a highly specialized component. Therefore, let's figure it out.

Between the server and a regular worker or gaming computer there is a significant difference due to the responsibility for the tasks being solved. Therefore, the requirements for the installed hardware are fundamentally different.

For server equipment operating 24 hours a day, it should not only be reliable, but fault-tolerant. In server DDR memory, this is done in different ways.

Hardware support

In particular, it is installed on servers, which differs from the usual one by the presence of an additional microcircuit that acts as a buffer. It is smaller in size and is located in the center of the bar, so you can easily distinguish such a module. Usually, 1 buffer is installed for every 8 ordinary chips. What is it for?

The fact is that on modern motherboards, the RAM controller is an integral component of the processor. But since when simultaneously accessing several memory modules, it is exposed to serious current loads (due to a change in the electrical capacity of the chip during the "write-read" process), then it needs reliable protection... This function is performed by the buffer of the server register memory module. Without it, the server processor could easily fail during intensive work.

Programmatic way

In the process of reading information from memory microcircuits, an error may occur due to the influence of external factors. Do not be surprised, the neutrons of cosmic and powerful electromagnetic radiation can easily change the state of the memory bit.

To minimize the consequences of such a situation, the ECC (Error Correcting Code) function is used, which is also applied to some individual modifications. conventional memory... The algorithm used in it is capable of independently detecting and correcting errors by mathematical methods of processing a digital code. Needless to say, how important is this for the stable operation of the server?

Immediately I want to draw the attention of readers to the marking of server memory. You may be aware that ECC modules are identified by the letter "E". But this does not mean at all that such a module is a server one.

Remember: only register memory can be server-side, and already ECC is its required component. The server memory bar is designated by letters in the marking "R" or "REG", which means "Registered". The very type of such RAM is called FB-DIMM (Full Buffered).

It is also worth adding that the fault tolerance of the server RAM is ensured not only by the above methods. In addition to this, it undergoes special tests that simulate conditions of long-term operation (heating up to 100 ° C) under intense load. The memory modules are then tested for compatibility with different software and hardware server platforms. This makes it possible to identify defective modules in a short time. If their number is more than the prescribed amount (2 bars out of 10,000 pieces), then the whole batch is rejected.

Differences that matter

As you can see, the reliability of server RAM is simply amazing and it is quite natural that some users want to use it on a regular computer. But, my dear friends, there are several nuances here and I want you to know about them:

• The exchange of information through the buffer will require additional clock cycles from the processor, in addition, the ECC algorithm is used, which also requires additional processing time. As a result, the server memory demonstrates a much lower operating speed;

• You are well aware that the presence of additional chips and high requirements for the quality / reliability of the product significantly affect the final cost of the product. Therefore, the price of server memory is much higher than usual;
• And finally, the main information for those who want to know: will register memory work on a regular motherboard? Will. But not every one. Both server and gaming support different trims. It is they who may have the ability to work with the RAM buffer. This technology allows you to significantly increase the amount of RAM without creating an additional load on the processor. Therefore, always check specifications your motherboard and you may be able to install reliable server memory on your PC.

Now you know how the server RAM differs from the usual one. There are not many differences, but they are quite significant. This concludes my story and say goodbye to you. I hope to please you soon with new interesting articles.

See you and all the best to you!

By virtue of its specificity, server topics are a relatively rare guest on the covers of IT periodicals. If you take an interest in the quantitative ratio of "server" and "desktop" information existing on the Internet, you can get approximately 1:20. As for even more subtle matters, such as organizing a data storage system on enterprise-scale servers, it is very difficult to obtain such knowledge. Today we will touch upon, perhaps, one of the "quietest", but still present areas of the market for professional components, namely server memory.

Since the very phrase "server memory" is rather an abstract slang expression containing too many different meanings, we decided to combine the "general education" part with the definition of the economic feasibility of the existence of this direction as such.

What is Server Memory? To conduct our conversation more substantively, for a start, it would be nice to understand the terminology and explain what is meant by this phrase in this publication. So, server memory (hereinafter referred to as SP) is memory modules with parity and error correction, as well as additional functionality to ensure greater stability (register buffered memory), created according to standards different from those used in desktop products and certified for use in servers from A-brands... We will not pretend to have this definition included in the textbook, but it seems to us that it reflects the essence.

The second question that I would like to discuss is how does server memory differ from desktop memory, in addition to the above additional bits, registers and buffers?

Differences between server and desktop memory

Manufacturers

The number of brands on this market is much more modest than on the “tabletop” field. In order not to get confused about who is doing what and for whom, we will divide the companies that issue the joint venture into several subcategories.

A-brands- memory created for specific server manufacturers with their unique markings on chips and modules. All top-tier developers (HP, Dell, etc.) typically take this approach to maximize their overall bottom line. In this case, it is probably not worth focusing on who specifically produces this or that module and / or microcircuit (it can be any company that has won a tender or has direct contracts). The most important thing to know: modules sold, for example, under the Dell trademark, are exactly compatible with Dell servers, and are 100% likely to work in them.

Chip A-brands (manufacturers of memory chips and modules on them)- companies engaged in the production of both microcircuits and memory modules under their own trademark. This category includes Micron, Samsung, Hynix, Quimonda (formerly Infineon). By and large, it is they who regulate the memory market as a whole, since in total they produce about 70% of DRAM microcircuits. All of the above companies have product lines of server modules of any standards. Of course, a tight connection to production allows us to have more competitive prices compared to companies focusing exclusively on server brands, but in this case there is another side of the coin - difficulties with certification. For example, a change in the series or generations of microcircuits leads to a change in marking (sometimes only chips, and sometimes modules), which requires new tests from server manufacturers to issue a conclusion on whether new memory to operate on their systems or not. There are situations when, under identical markings, there are essentially two products with different characteristics on the market (and both are original), which gives a lot of headaches to server builders.

Modular A-brands (manufacturers of modules on third-party chips) is the most common category. Among them are such famous names as Kingston, Corsair, Transcend, Apacer. Actually, such companies in relation to the joint venture are often called "test" ones, because their engineers spend most of their time just testing modules for operability with commercially available server platforms. As a result, a situation arises that is in many ways similar to JVs from server A-brands, in addition, such firms have much less problems associated with labeling. Therefore, the end consumer or the server assembler can easily obtain information that the module with “such” marking is suitable for use in “such and such” server, and it does not matter on the basis of the microchips of which manufacturer it is made.

All three approaches have their positive and negative sides, but in the near future it is not necessary to expect any changes in the presence or arrangement of brands on the JV market.

fault tolerance

In relation to the joint venture, such a rather desktop term as "reliability" is usually replaced by "fault tolerance", which more accurately reflects the meaning. Since such equipment must work without interruption 99.9% of the time from the moment it is put into operation, much more rigorous approaches are used in production and testing than in the manufacture of desktop products.

For example, the technology of "artificial aging" provides identification of manufacturing flaws within two days - during testing, the server modules are heated to 100 ° C, which allows them to quickly bring them into a state corresponding to two months of operation. Next, in the set of tests that heavily load the memory subsystem, there is a check for compatibility of modules with various server platforms, which takes about another day. As a result, a joint venture with a rejection rate of about 0.02% (one module per five thousand) gets into the channel.

In the same section, it is worth saying a few words about such a concept as "successful model", which again came from the desktop world. It is a well-known fact that there are “successful” video cards that work equally well on any platform, “successful” hard drives that are compatible with most controllers, and “successful” memory modules that provide stable operation with almost all motherboards. As for the joint venture, everything is exactly the opposite. The main criterion that the manufacturer is guided by is the absence of "unsuccessful" models, because a high-quality joint venture bar should work everywhere and always and without any reservations. So, if a product from brand X did not work with the server of brand Y, then such a joint venture will most likely not be allowed on the conveyor until the reason is determined. Of course, no one can afford a similar approach with regard to components for mainstream computers.

Criterias of choice

The end customer, when choosing memory when assembling or upgrading his computer, is usually guided by the following criteria: brand (this also includes a guarantee), price, test results. In other words, it is important for him who the manufacturer is, what timings and frequencies can be obtained, and how much they will have to pay for all this. If you go up a notch and see what principles the assembly company is guided by, then the price immediately comes to the fore. She, in view of the very tough competition in the market, usually chooses the cheapest option from the hassle-free ones.

With the joint venture, the situation is as follows - integrators, as a rule, are primarily guided by the experience of operating certain modules in certain platforms and are guided by one (maximum two) suppliers who are able to strictly comply with conditions such as stability of supply and quick resolution of technical issues with the manufacturer. if they occur. Although the price is, of course, an important component, it is far from the determining factor. If a joint venture from one brand turns out to be 20% more expensive than another, but at the same time provides better compatibility, then the choice will most likely fall on her.

What Determines Demand for Memory: Server Vendor Opinions

Evgeny Bobruiko

everest server hardware product manager

In accordance with the company's policy, we try to offer the optimal solution for specific applications, always with a small margin for the future. If the client has "outgrown" his configuration, then in many cases it is more expedient for him to purchase a more modern and powerful server, and transfer the old one to other, less responsible and time-consuming tasks.

Server modernization services are in very low demand in our company (about 2% of systems are exposed to it). After all, a prematurely arising problem of improving the memory subsystem indicates either a significant increase in streaming tasks for the client (for example, due to an increase in the staff), or an error of the integrator who proposed an ineffective solution.

As for memory types, FB-DIMM has excellent performance for streaming data, which is very much in demand when working with databases (especially OLAP), and also allows you to install a significant amount of RAM in the server. On the other hand, it has a high latency, which is not always good. For DDR2, this figure is lower, but it also has a lower throughput... It is to combat high latency that Intel has a good "weapon" - a large and shared cache for two cores in Woodcrest.

On the whole, it seems to me that FB-DIMM has very good prospects, since DDR2, due to the parallel method of data transfer, approaches the "ceiling" as the frequency rises. However, I do not exclude that at first Intel may make a budget version of the system logic based on DDR2.

Andrey Tishchenko

Entry company manager

In my opinion, modernization of servers is a thankless task, since the entire component base is outdated and many problems cannot be solved simply by adding memory. Most of our customers are growing companies, constantly updating their server park, they adapt old models for less resource-intensive applications without modernization. Therefore, requests for installing additional memory are rare for us, such sales do not exceed 2-3% of the total supply.

I must say that there is no competition between DDR2 and FB-DIMM as such - there is a planned transition of the two main chipmakers to a new architecture. The popularity of this or that memory depends on who this period will be easier for. Intel has taken a big step forward by pushing the limits of the shared processor bus and lowering the power consumption of new CPUs. Nevertheless, the bet on FB-DIMM may work against the company in the near future. Compared to DDR2, its performance is worse: higher latency, power consumption and heat dissipation, and the cost of modules is about 10%.

With the transition to Socket 1207 (Rev F) and the adaptation of the memory controller on the core for DDR2, AMD retains the ability to work with memory at the core frequency, use the most popular standard, and scalability of multiprocessor multi-core platforms. In the future, the company plans to switch to FB-DIMM memory, but sees its trump cards in something else. Figuratively speaking, if Intel constantly stimulates developers of new types of memory and maintains high rates of DDR-DDR2-FB-DIMM evolution, AMD is more focused on meeting the price / performance / power consumption criterion.

Igor Przhegarlinsky

commercial director of the company "Onyx"

If earlier a 32-bit operating system was installed on most servers, which imposed restrictions on the amount of memory up to 4 GB, then with the transition to 64-bit operating systems, the limit will increase to 32 GB (for 1-4-processor servers on Windows based Server 2003 Standard Edition).

With the release of new Intel processors(Dempsey and Woodcrest) and AMD (Socket F) FB-DIMM and DDR2-667 ECC Reg. Both chip makers have long abandoned support for a single standard, and the competition between memory types will, as a result, be reduced to competition between chip manufacturers.

The bulk of server memory is currently used in new systems - the share of modules sold for upgrades does not exceed 5%.

Performance

Very for a long time The joint venture lagged significantly behind the desktop one in its speed characteristics. Suffice it to recall that the DDR400 standard, which managed to become widespread for desktop systems and laptops, came to server systems only with the advent of the Opteron. Even in modern chipsets for powerful workstations, they continued to use register buffered DDR266 for a long time.

The next leap in professional systems is Intel based the use of DDR2-400 became - this despite the fact that in desktops, the start of DDR2 began at 533 MHz. For reference, note that for Itanium 2-based servers, only DDR200 with 128-bit access was generally used to provide the necessary bandwidth. Reasons why platform creators chose more low frequencies, are clear: increasing the reliability and reducing the load of the memory controller integrated with the main set of logic.

Today, server technology is also required maximum performance, which forces us to use the most modern standards that are not inferior, and sometimes even surpass the existing ones for desktop systems. Pay attention to the specifications of the latest server platforms - the total performance of the northbridge buses for Intel chipsets and integrated controllers for Opteron can exceed the fantastic mark of 30 GBps. And most importantly, at such speeds, you need to provide a 24/7 mode of operation when running very resource-intensive applications.

Perhaps the situation is even more complicated with the memory subsystem. Today's standards are FB-DIMM 667 MHz for Intel and register buffered DDR2-667 with double parity for Opteron. The amount of memory to ensure comfortable work is constantly increasing, and, as you know, the likelihood of an error in RAM grows exponentially with increasing volume. As a result, manufacturers of modules and, first of all, JV microcircuits have to look for ways to ensure reliability no less than with previously used DDR200 / 266 standards, as well as with increased volumes, now reaching 32 GB, huge frequencies of 667 MHz and maintaining the difference in cost is no more than 40% compared to desktop modules.

Price

Although the JV market is not subject to strong fluctuations, which are often observed in the desktop segment, at the same time, it is quite dynamic, and such methods of competitive struggle as dumping, marketing promotions, OEM deliveries at reduced prices, etc. are not excluded. e. Today, the cost of JV modules differs on average by 20-50% from similar desktop modules in terms of volume. On the one hand, this is not a little, on the other, you can recall a more complex technical implementation (additional microcircuits for parity and buffering control), the need to conduct a set of tests after the product leaves the assembly line, certification from the server manufacturer and, of course, a lifetime warranty. As a result, it turns out that the vendor's earnings on JV modules are hardly much more than on desktop "slats". And the modern market requires constant price reductions: just remember that FB-DIMMs began to fall in price literally from the day they appeared on the free market. So, if at first the cost of FB-DIMM was about twice as high as the joint venture of DDR2 and DDR standards, now this difference is much more modest and amounts to about 30-40%.

What Determines Demand for Memory: Supplier Opinions

Elena Krivoshienko

Head of the sales department of memory modules and flash products of the Kiev-TEK company

According to our data, the volume of the Ukrainian segment of server memory accounts for 10-13% of the memory market as a whole, which in financial terms equals approximately 5-7 million dollars per year.

Over the past months of 2006, the structure of server modules sales has changed somewhat. DDR and DDR2 are sold in roughly the same quantities, with quite a few DDR modules being ordered recently for server upgrades. As for FB-DIMM, today their share in the total sales structure is no more than 2%.

In quantitative terms, the server memory market is expected to grow. It can be assumed that in the next six months the sales structure will shift towards DDR2. Regarding FB-DIMMs, I believe that their share will gradually increase, although in the next six months it is unlikely to be significant. Solutions using of this type memory is still very expensive - primarily due to the cost of processors.

Dmitry Borovsky

General Manager of TNG

Due to the difficult political situation this year, the corporate segment of the IT market has slowed down quite strongly. This has led to a decrease in the supply of end-to-end solutions based on servers. It is hoped that the situation will change at the end of the year, but it is difficult to guarantee that the demand for components, including server memory, will be fully satisfied during the hot season. Based on this, the annual volume of the server memory market in Ukraine can be estimated only roughly - according to our forecasts, it will be from 40 to 60 thousand modules, and in financial terms - from 4 to 5 million dollars.

I would like to note that in 2006 the sales of DDR333 server memory sharply decreased, practically the same thing happens with DDR400 - their share is now less than 5%. The main product today is DDR2-400 modules, and the demand for FB-DIMMs is due to the availability of motherboards for them on the market. FB-DIMM deliveries began only in the III quarter, and so far they occupy less than 5% of our sales (however, the upward trend of this indicator is evident).

There is no particular difference between trends in the domestic and international markets as a whole. For systems where fault tolerance is a critical factor, manufacturers prefer memory from well-established vendors. Perhaps the only difference is that large world brands mainly use first-hand server memory in their products - from Samsung, Hynix, Micron. On the local market, there is a significant demand for modules from Corsair, Kingstone, etc.

Andrey Semenovsky

CEO of Nebesa

The server memory segment is just a part of the server market, however, due to the high cost of modules, it plays a more prominent role than memory in the desktop market. While desktop PCs are concerned with the release of successful memory models around which marketing is built, for servers it is the absence of unsuccessful ones. Problems with the availability and quality of server memory can lead to costs that are many times higher than the price of modules, which means that the responsibility for delivery times, the declared compatibility of models and quality in this case is an order of magnitude higher. And given the low ROI of server memory, you can imagine how difficult this segment is from a business point of view.

Of the peculiarities of the domestic market, I would like to note the rather high potential of Ukrainian server collectors. The volume of memory consumption is about 6-8 thousand modules per quarter, and the average price of a board is close to $ 150.

Changes in the sales structure of memory depend on those in lineup platform manufacturers (primarily Intel and AMD). By the time FB-DIMM was released, the ratio of DDR2 to DDR sales was 70:30. With the advent of fully buffered memory, a transition process began: the demand for platforms with DDR2 support is noticeably decreasing, and with FB-DIMM, they are not purchased too actively due to sufficient high price and underdevelopment. It is noteworthy that during this period DDR sales increased - their share in the supply structure approached 50%.

Victor Shcherbyak

head of the sales department of the company "ASBIS Ukraine"

Release of new server rooms operating systems allowed to significantly increase the maximum amount of memory in the system (earlier versions of the OS had significant restrictions on this parameter). Therefore, sales of modules both in piece and in monetary terms increased. According to our data, the server memory segment today accounts for about 5% of the total market for this product.

The demand for DDR has significantly decreased with the advent of new server platforms. The largest sales are now accounted for by DDR2 modules, the implementation of FB-DIMMs is also growing, although the latter's share is still insignificant. According to my estimates, the sales volumes of both types of memory are likely to be equal by the end of the year.

In general, servers are required from year to year more and more scalability, flexibility, capacity, speed of operation, as well as reliability and safety of investments. Based on new technologies, server memory manufacturers are releasing modules to achieve these improvements.

Ukrainian realities

According to the information available from integrators, about 10,000 servers are sold in Ukraine per year (let's clarify: not computers acting as a server, but systems using a joint venture). Even if this figure is too optimistic, the bottom line is that the number of JV modules sold is approximately 20,000 "strips", of which about a third is used to modernize previously assembled systems. For averaging, let us assume that the cost of one module is $ 100, therefore, the total volume of the joint venture segment in our country is approximately $ 2 million. Moreover, the number of firms offering such products does not exceed five, and they mainly work with vendors such as Kingston. Samsung and Hynix, of which the first two share about 70% of the Ukrainian market.

Probably, the information given in this article will seem too "basic" for some, but we think that for the first topic of the issue, devoted to server memory, it clearly will not hurt. And in more detail with the technical aspects of this type of product, we invite you to get acquainted in the next material.

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Hello, friends! In this article, we have tried to answer many of your questions regarding RAM. ? How do I know what kind of RAM I have installed and how much? How to choose the right RAM for your computer. How do you know if your RAM is working in dual channel mode or not? Is it better to buy one 8GB DDR3 memory stick or two 4GB memory sticks each? And finally.

• If you are interested, or, also read our articles.

1. Hello admin, a friend of mine asks to install more RAM for him. The computer properties show the size of 2 GB. Turned off the computer, opened system unit, there is one bar of RAM, they took it out, but there are no designations on it. Interestingly, it was not possible to determine the model either. motherboard... The computer was bought a long time ago, and accordingly the question arose - how to find out the type of RAM that it needs? After all, RAM differs in type, frequency and timings.
2. Hello everyone! I wanted to buy additional RAM, took off the cover of the system unit, took out the RAM bar and I can not decipher the information printed on it, it just says serial number that's all. It is completely unclear at what frequency it works and what type it has, DDR3 or DDR2. How to distinguish DDR3 memory from DDR2, how do they differ in appearance?
3. I have one 4 GB DDR3-1600 memory stick in the system unit, I want to put another 4 GB stick, but working at a higher DDR3-1866 frequency. Will my computer function normally, and most importantly, in dual channel mode?
   My friend installed three RAM strips of different size and frequency in the system unit. Is this allowed? But what is strange, his computer works fine!
4. Tell me how to check if my RAM is working in dual channel mode or not? And what conditions are needed for my memory to work in dual-channel mode. Same volume? Same frequency or same timings? How much faster the computer runs in dual-channel mode than in single-channel mode. They say that there is also a three-channel mode.
5. What will work better, two 4 GB RAM sticks in dual-channel mode, or one 8 GB stick, respectively, will the memory operation mode be single-channel?

To find out all the information about a RAM module, you need to carefully consider it, usually the manufacturer marks the RAM with proper information about the frequency, volume and type of RAM. If there is no such information on the module, then you need to find out everything about the motherboard and installed processor, sometimes this action turns into a whole investigation.

1. Important notes: Friends, do not forget that All new processors have Intel Core i3, Intel Core i5, Intel Core i7 the RAM controller is located in the processor itself (it used to fill the north bridge of the motherboard) and the memory modules are now directly controlled by the processor itself, the same applies to the latest AMD processors.
2. This means that it doesn't matter what frequency of RAM your motherboard supports. It is important what frequency of RAM your processor supports. If your computer has a processorIntel Core i3, Intel Core i5, Intel Core i7, then the officially supported memory standards of these processors: PC3-8500 (DDR3-1066 MHz), PC3-10600 (DDR3-1333 MHz), PC3-12800 (DDR3-1600 MHz), it is at these frequencies that your RAM will work, even if the passport of the motherboard indicates that the motherboard can work with RAM strips high frequency PC3-19200 (DDR3-2400 MHz).
3. It's another matter if your processor with unlocked multiplier, that is, with the letter "K" at the end, for example CPU Intel Core i7-4770 K, 3.5 GHz. An unlocked multiplier means that in a computer with such a processor, you can install memory sticks of the highest frequency, for example, DDR3-1866 MHz or DDR3-2400 MHz, such a processor can be overclocked and during overclocking the RAM will operate at its own frequency of 2400 MHz ... If you install the RAM bar DDR3-1866 MHz or DDR3-2400 MHz into a computer with a conventional processor, that is, with locked multiplier without letter" K ”at the end, for exampleIntel Core i7-3770, 3.9 GHz, then such a bar will work at best at a frequency DDR3-1600 MHz, and at worst the computer won't boot. Therefore, buy RAM suitable for your processor.
4. Concerning processorsAMD last years, they work with memoryPC3-10600 (DDR3-1333 MHz).

How to find out all the information about the installed RAM?
Firstly, on the RAM bar itself there should be all the information you are interested in, only you need to read it correctly. I do not argue, there are memory bars on which there is practically nothing, but we can also cope with them.
For example, let's take a Hynix RAM bar, it contains the following information: 4 GB PC3 - 12800.

Which means the following:

firstly, the volume of 4 GB,

secondly, 1Rx8 - Rank is a memory area created by several or all chips of a memory module, 1Rx8 are single-sided memory ranks, and 2Rx8 are double-sided memory ranks.

As you can see, this bar does not say that it is DDR2 or DDR3, but the bandwidth of PC3-12800 is indicated. PC3 - the designation of the peak bandwidth belonging to the DDR3 type only (for DDR2 RAM, the designation will be PC2, for example PC2-6400).

This means that our Hynix memory stick is of the DDR3 type and has a bandwidth of PC3-12800. If the bandwidth of 12800 is divided by eight, we get 1600. That is, this DDR3 memory bar operates at 1600 MHz.

Read everything about DDR2 and DDR3 RAM on the website

http://ru.wikipedia.org/wiki/DDR3 and everything will become clear to you.

Let's take another RAM module - Crucial 4GB DDR3 1333 (PC3 - 10600). This means the following: 4 GB, DDR3 memory type, frequency 1333 MHz, the bandwidth of PC3-10600 is also indicated.

Let's take another bar- Patriot 1GB PC2 - 6400.

The manufacturer is Patriot, the volume is 1 GB, the bandwidth of PC2 is 6400. PC2 is the designation of the peak throughput belonging to the DDR2 type only (for DDR3 RAM, the designation will be PC3, for example PC3-12800). Divide the 6400 bandwidth by eight and get 800. That is, this DDR2 memory stick operates at 800 MHz.

Another plank- Kingston KHX6400D2 LL / 1G
Manufacturer Kingston, bandwidth 6400, type DDR2, volume 1 GB. Divide the bandwidth by 8, we get a frequency of 800 MHz.
But on this bar of RAM there is more important information , it has a non-standard supply voltage for the microcircuits: 2.0 V - it is manually set in the BIOS.

RAM modules differ in the size of the contact pads and the location of the cutouts. A notch will prevent you from installing a RAM module in a slot that is not intended for it. For example, you won't be able to install a DDR3 memory bar into the DDR2 slot.

Everything is clearly visible in this scheme.

Sometimes there will be no understandable information on the RAM module, except for the name of the module itself. And the module cannot be removed, since it is under warranty. But even by the name you can understand what kind of memory it is. for instance

Kingston KHX1600 C9D3 X2K2 / 8G X, it all means:

KHX 1600 -> Operative operates at 1600 MHz

C9 -> Timings (Delays) 9-9-9

D3 -> DDR3 RAM type

8G X -> 4 GB volume.

You can just type the name of the module in the search engines and you will find out all the information about it.
For example, the information of the AIDA64 program about my RAM. RAM modules Kingston HyperX installed in RAM slots 2 and 4, memory type DDR3, frequency 1600 MHz
DIMM2: Kingston HyperX KHX1600C9D3 / 4GX DDR3-1600 DDR3 SDRAM
DIMM4: Kingston HyperX KHX1600C9D3 / 4GX DDR3-1600 DDR3 SDRAM

Can I install RAM sticks with different frequencies in my computer?

The frequency of the RAM does not have to be the same. The motherboard will set the frequency for all installed RAM strips to the slowest module. But I want to say that often a computer with bars of different frequencies is unstable.

Let's do a simple experiment. For example, let's take my computer, it has two identical Kingston HyperX RAM modules, DDR3 memory type, 1600 MHz frequency.

If I run the AIDA64 program in my Windows 8, it will show such information (see the next screenshot). That is, the program AIDA64 shows the simple technical characteristics of each of the RAM strips, in our case both strips have a frequency1600 MHz. But the programAIDA64 does not show at what frequency exactly the ramps are working now, you need to look at this in another program called CPU-Z.

If you run free program CPU-Z and go to the Memory tab, then it will show at what frequency your RAM sticks work. My memory works in Dual mode, 800 MHz, since DDR3 memory, its effective (doubled) speed is 1600 MHz. This means that my RAM sticks work exactly at the frequency for which they are intended for 1600 MHz. But what will happen if next to their RAM sticks operating at a frequency 1600 MHz I will set another bar with frequency 1333 MHz !?

Let's install an additional DDR3 memory stick in my system unit, operating at a lower frequency of 1333 MHz.

We look at what AIDA64 shows, the program shows that an additional 4 GB bracket is installed, the frequency is 1333 MHz.

Now let's run CPU-Z program and let's see at what frequency all three bars work. As you can see, the frequency is 668.7 MHz, since the memory is DDR3, its effective (doubled) speed is 1333 MHz.

That is, the motherboard automatically set the operating frequency of all RAM modules to the slowest 1333MHz module.

Is it possible to install RAM sticks into the computer with a frequency higher than the motherboard supports? The most important thing is that the frequency of the RAM is supported by your motherboard and a processor (there is information about processors at the beginning of the article). For example, let's take the mother's Asus board P8Z77-V LX, it supports modules operating at 1600/1333 MHz in nominal mode and 2400/2200/2133/2000/1866/1800 MHz in overclocked mode. All this can be found in the passport for the motherboard or on the official website http://www.asus.com

It is not advisable to install RAM strips into the computer with a frequency higher than the motherboard supports. For example, if your motherboard supports a maximum frequency of 1600 MHz RAM, and you installed a RAM module operating at a frequency of 1866 on your computer, then in the best case this module will operate at a lower frequency of 1600 MHz, and in the worst case the module will work at its own frequency 1866 MHz, but the computer will periodically restart itself or you get when you boot your computer blue screen, in this case you will have to enter BIOS and manually set the frequency of the RAM to 1600 MHz.

Timings(signal delay) determine how often the processor can access the RAM, if you have a quad-core processor and it has a large L2 cache, then too long timings are not terrible, since the processor is less likely to access RAM. Can I install RAM sticks with different timings in my computer? Timings do not have to be the same either. The motherboard will automatically set the timings for all strips for the slowest module.

What conditions are needed for my memory to work in dual-channel mode Before buying RAM, you need to study as much information about the motherboard as possible. All information about your motherboard can be found in the manual that came with it upon purchase. If the manual is lost, you need to go to the official website of your motherboard. Also, the article "How to find out the model and all information about your motherboard" will be useful to you.
Most often nowadays there are motherboards that support the modes of operation of RAM described below. Dual Mode (most common)- upon closer examination of the motherboard, you can see that the RAM slots are painted in different colors. This is done on purpose and means that the motherboard supports a two-channel mode of operation of RAM. That is, two RAM modules with the same characteristics (frequency, timings) and the same volume are specially selected and installed in the RAM slots of the same color.

If your computer has one RAM stick, but the motherboard supports dual-channel mode, you can buy a RAM strip of the same frequency and volume and install both strips in DIMM slots of the same color.

Is there an advantage of the two-channel mode over the single-channel

At routine work on a computer, you will not notice the difference, but when working in applications that actively use RAM, such as Adobe Premiere Pro(video editing), (Canopus) ProCoder (video encoding), Photoshop (working with images), games, you can feel the difference.

Note: Some motherboards will work in dual channel mode even if you install different memory modules in the same color DIMM slots. For example, you will install a 512MB module in the first DIMM slot, and a 1GB bracket in the third slot. The motherboard activates the dual-channel mode for the entire volume of the first strip 512MB, and for the second strip (which is interesting) also 512MB, and the remaining 512MB of the second strip will work in single-channel mode.

How do I know if my RAM is working in dual channel mode or not? Download the free CPU-Z program and go to the Memory tab, look at the Channel parameter in our case - Dual, which means the RAM works in dual-channel mode. If the Channels parameter is Single, then the RAM works in single-channel mode.

Triple Mode (three-channel mode, rare)- you can install from three to six memory modules. Which will work better, two 4GB sticks of RAM in dual-channel mode, or one stick, but 8GB in single-channel mode?

In my opinion, during normal work on a computer they will work in the same way, personally I did not notice much difference. I worked for a long time on a computer with one large stick of RAM and the performance was the same as on exactly the same computer with two sticks of RAM working in dual-channel mode. A survey of friends and acquaintances of system administrators strengthened me in this opinion. But when working with programs that actively use RAM, for example, Adobe Premiere Pro, Canopus ProCoder, Photoshop, games, a computer with two sticks of RAM will work faster.

Is it possible to install several RAM strips of different frequency and volume in a computer?

Of course you can, but not desirable. The computer will work more stable if it implements the operating memory mode recommended in the motherboard passport. For example, two-channel mode.