The RAM market is quite conservative. With the exception of the appearance of fundamentally different types of modules every two to three years and the regular update of JEDEC standards regarding clock frequencies, any technological innovations are extremely rare and even less often go beyond changes in the cooling system or improving the appearance. In this regard, it is worth paying special attention to the Enhanced Performance Profiles (EPP) technology, recently announced by NVIDIA as an open standard.

Any DDR2 memory module includes a Serial Presence Detect (SPD) microchip, into which the manufacturer and model name, serial number, as well as the nominal frequencies and timings according to JEDEC requirements are stitched. However, in order to ensure full compatibility with motherboards, memory manufacturers often indicate in the SPD the safest delays, far from the real parameters of the modules - thus, in order to achieve optimal performance (and even more so overclocking), the user has to manually set the timings through the BIOS. On the other hand, the JEDEC specifications for the SPD content do not presume to store such important parameters as supply voltage and Command Rate, as well as some fine settings, in particular a number of Drive Strength parameters. NVIDIA jointly with Corsair took the initiative to create a unified open industry standard for optimized automatic detection of memory parameters.

The developers were faced with the task of both improving the nominal performance of the memory subsystem and facilitating the overclocking process - making it more "transparent" for beginners and providing a good base for experiments for experienced overclockers. To achieve these goals, the contents of the SPD microcircuits were supplemented with the necessary parameters, ensuring full compatibility with the JEDEC requirements, including maintaining the existing "safe mode" to guarantee the POST procedure under any conditions. The result of the work was officially presented on May 15 of this year in the form of the open standard Enhanced Performance Profiles (EPP), which received from NVIDIA the second name "SLI-Ready Memory".

Corsair TWIN2X 2048-6400C3

Memory type PC2-6400 (DDR2-800)

Volume 2 × 1024 MB

Nominal supply voltage 2.2V

Default timings for PC2-6400 mode 3-4-3-9

Estimated price$440

Is provided Unikom Consulting, www.unikom.com.ua

Impressive timings at DDR2-800; EPP support; SLI certification

Not a record maximum clock speed

Optimal memory for working at low timings

From a technical point of view, the implementation of EPP is quite simple. To use its capabilities, you need the appropriate memory modules, as well as a motherboard with a BIOS that can read extended information from the SPD. The memory capacity of the SPD chip is 256 bytes, of which only the first 99 are filled according to JEDEC requirements. Additional parameters included in the EPP specification are located in the 99-127 byte zone and do not in any way affect the operation of the modules on motherboards that do not support EPP.

The first chipset with EPP support was NVIDIA nForce 590 SLI, but this list should be expanded in the future. The open nature of the standard implies the absence of any royalties, and the creators invite all interested manufacturers to support their initiative. Despite the fact that the development was carried out by NVIDIA in cooperation with Corsair (which presented the first products with EPP on the day of the standard's announcement), today various kits supporting this technology are already available in the assortment of Kingston, Crucial and OCZ Technology, and other manufacturers are planning to announce their EPP -compatible modules coming soon. Optionally, the manufacturer can submit its EPP modules for NVIDIA certification for compatibility with SLI systems, after which it receives the right to place the "SLI-Ready" logo on the product packaging - at the time of this writing, there are already 17 memory kits in the list of certified products from all four the brands mentioned. It is important to note that EPP support should not affect the price of the modules, as no technological changes are foreseen.

Let's take a closer look at what additional information in the SPD is, as defined by the Enhanced Performance Profiles specifications. In full accordance with the name, the standard assumes the possibility of flashing several profiles into the module for operation in different conditions, for example, optimized for the maximum clock frequency or minimum timings. The 28-byte EPP range allows the manufacturer to define either two full profiles or four short ones. Detailed information on specific parameters is contained in the table, therefore, we will note only the most interesting points. First, even in abbreviated form, EPP profiles are of significant value, since they allow you to achieve maximum memory subsystem performance without unnecessary manipulation of BIOS settings. Actually, the introduction of EPP for the first time gives non-overclocking users the motivation to purchase high quality modules with improved timings or high clock speed potential. Especially useful in this respect is the automatic setting within a wide range of the supply voltage - a parameter whose manual increase quite justifiably frightens unprepared users. Secondly, the list of fine tunes included in the full EPP profile is impressive. Of course, with their help, enthusiasts will be able to make the most of all the possibilities of memory. Interestingly, without waiting for the JEDEC standard, Cycle Time = 1.875 ns, corresponding to DDR2-1066, was added to the EPP parameter list, but there are no other non-standardized values ​​(for example, for already existing DDR2-1100 modules).

Corsair TWIN2X 2048-8500C5

Memory type PC2-8500 (DDR2-1066)

Volume 2 × 1024 MB

Nominal supply voltage 2.2V

Default timings for PC2-8500 mode 5-5-5-15

Estimated price$490

High overclocking potential; EPP support; SLI certification

A premium all-in-one overclocking memory kit

We carried out a practical test of the EPP technology using the first modules of this type that appeared in Ukraine - Corsair TWIN2X2048-8500C5 and TWIN2X2048-6400C3 (unfortunately, EPP-compatible products of Kingston and OCZ Technology are not yet presented in our market) and a reference motherboard based on NVIDIA nForce 590 SLI - Foxconn C51XEM2AA. Actually, thanks to their impressive characteristics, the aforementioned Corsair memory kits deserve attention even without taking into account EPP support and the presence of SLI certification. The older model of the DDR2-1066 type is focused on achieving the maximum clock frequency and in practice is capable of overclocking to frequencies above 1150 MHz at a voltage of 2.3 V (nominal - 2.2 V), and TWIN2X2048-6400C3 provides operation at a frequency of DDR2-800 at CAS Latency = 3. In more detail, the results of testing both memory kits are shown in the diagram.

After installing memory modules with Enhanced Power Profiles support on the Foxconn C51XEM2AA motherboard ("Computer Review", No. 36, 2006) during the POST procedure, the BIOS reports that it is possible to enable the SLI-Ready Memory mode. There is a corresponding item in the memory settings tab, and when it is activated, a window appears with the choice of the operating mode: simple enable EPP settings without changing the system bus frequency; automatic overclocking to 1, 2, 4, 8 or 16% of the nominal or MAX OC mode, in which the system tries to boot at the closest possible clock frequency specified in the profile. In our case, when installing the TWIN2X2048-8500C5 kit, the choice of the last item led to a decrease in the processor multiplier and setting the memory frequency to 1062 MHz (the closest value to the 1066 MHz EPP SPD). Alas, it should be noted that the implementation of the EPP control interface on the motherboard we used was not very successful, despite the fact that this particular BIOS was developed in cooperation with NVIDIA. So, on the ASUS M2N32-SLI board, the management of settings profiles and automatic overclocking is split into two separate menu items - much more intuitive.

The contents of the EPP segment of the SPD code can be viewed after booting the operating system using utilities such as Lavalys Everest or NVIDIA nTune. Perhaps the best method for using EPP by enthusiasts will be: starting from the available recommended timings, setting all values ​​manually and looking for more effective options based on personal experience. But for novice overclockers and those who do not want to overclock a computer at all, the flashed profiles will come in handy for their intended purpose - to safely improve PC performance.

Corsair TWIN2X2048-8500C5 modules have two full EPP profiles - Performance and Frequency. In the first case, the timings are automatically set at the level of 4-4-4-12-22-2T, which allows you to get a performance boost in the standard DDR2-800 mode for the AM2 platform. In the second, the timings are set to the "relaxed" mode 5-5-5-15-23-2T to smoothly reach frequencies above DDR2-1066 (manually or using the MAX OC automatic overclocking function). If the user did not manually set the supply voltage, when EPP is activated, it automatically changes to the 2.2 V recommended by the manufacturer.

Based on the results of our EPP health check, the following conclusions can be drawn. The technology is really doing its job as promised by the developers. Despite some non-transparency of BIOS settings on the Foxconn board, even an inexperienced user can improve the performance of his PC, feeling the benefits of using overclocking memory modules. Given that there are no additional costs for implementing EPP into memory modules, we can expect that the number of products supporting this standard will grow significantly in the near future. And thanks to its openness, there is hope that the list of EPP-compatible chipsets will become somewhat wider. For now, we can only recommend that owners of motherboards based on nForce 590 SLI pay attention to EPP-compatible kits when searching for memory modules.

EPP parameter table

Parameter	Possible values ​​for EPP	Support
		JEDEC SPD	Abbreviated EPP Profile	Full EPP Profile
CAS Latency	2, 3, 4, 5, 6	+	+	+
Minimum Cycle Time at Supported CAS	JEDEC + 1.875ns (DDR2-1066)	+	+	+
Minimum RAS to CAS Delay (tRCD)	JEDEC *	+	+	+
Minimum Row Precharge Time (tRP)	JEDEC *	+	+	+
Minimum Active to Precharge Time (tRAS)	JEDEC *	+	+	+
Write Recovery Time (tWR)	JEDEC *	+	+	+
Minimum Active to Active / Refresh Time (tRC)	JEDEC *	+	+	+
Voltage Level	1.8-2.5V	—	+	+
Address Cmd Rate	1T, 2T	—	+	+
Address Drive Strength	1,0+, 1,25+, 1,5+, 2,0+	—	—	+
Chip Select Drive Strength	1.0x, 1.25x, 1.5x, 2.0x	—	—	+
Clock drive strength	0.75x, 1.0x, 1.25x, 1.5x	—	—	+
Data Drive Strength	0.75x, 1.0x, 1.25x, 1.5x	—	—	+
DQS Drive Strength	0.75x, 1.0x, 1.25x, 1.5x	—	—	+
Address / Command Fine Delay	0, 1/64, 2/64, 31/64 MEMCLK	—	—	+
Address / Command Setup Time	1/2, 1 MEMCLK	—	—	+
Chip Select Delay	0, 1/64, 2/64, 31/64 MEMCLK	—	—	+
Chip Select Setup Time	1/2, 1 MEMCLK	—	—	+
* The range of values ​​fully complies with the JEDEC requirements for DDR2 modules (JC45).

OCZ, a well-known manufacturer of PC hardware for the enthusiast, decided to try to advertise itself with assistive applications. A clever utility called SPD-Z was announced on the official forum. As it is not difficult to guess from the abbreviation, it is designed to work with the service information of RAM modules. It should be noted that until now, none of the manufacturers of this kind have released utilities for free use that can harm hardware components if used incorrectly.

For unprepared users, a special algorithm of the utility was even written, according to which one can easily imagine what the program actually does.

advertising

The developers are positioning the product for the same category of enthusiasts. The utility allows you to reflash memory timings only on the modules of the aforementioned manufacturer. It is said that such manipulations can lead to improved performance and correct compatibility in some cases. The program checks the batch number of the chips, and is automatically sent to the server with an archive of compatible profiles. All the user has to do is to make sure that the system is not overclocked and is 100% stable (is it really not clear what kind of compatibility increase is in question?).

Good day everyone. Today we'll talk about how to choose RAM.

This next note owes its appearance to our esteemed readers, because it was from them (ie, you) that the bell came that I want to see everything and more from the category of "heavy artillery", that is. Well, since we, a project that can not only write, but also read in places (in particular, your comments :-)), in fact, here is another iron article for you about the "brains" of your PC, namely, RAM ...

As I said, initially it was a whole article, which was divided into two. You can find the first part, which talks about RAM in general (that is, the principles of operation, why it is needed and all that stuff).

In the introduction I would also like to say that this creation will take its place of honor in our "iron pantheon" of articles. Whoever has forgotten (or even hears it for the first time, that is, hello to newcomers ;-)) what was discussed there, I remind you - the materials tell you what you need to pay attention to when buying individual "spare parts" for your computer. Some of these works of art include: “Intel or AMD. Problems of choice "," How to choose the right fan (cooler) for the processor "," "and all that different from the tag" Selection criteria ".

I dare not detain you any longer, let's start ..

Basic introduction on characteristics and not only

How to choose the right RAM so that the performance of the PC increases and it quickly processes those applications / games that I could not even have thought of before? I think this question is being asked by a huge number of users of our (and not only) vast country.

And they do it right, that they are asked, because only at first glance we can say that everything is simple and understandable, but there are a lot of subtleties that we will now tell you about.

So, the first thing to keep in mind (before buying) - the choice of the "correct" memory is the key to the success of further overclocking your iron friend and to some extent avoids unnecessary material injections into the newly released piece of hardware.

Those. memory (for example, "overclocking"), allows you to keep the user's PC in a "vigorous" mood for quite a long time, due to the overclocking potential provided by the manufacturer.

It was not in vain that we said above that RAM and cache are used by the processor for data processing (and through the motherboard it consumes RAM resources). It’s not in vain, because it’s impossible to select a separate RAM from the same processor or motherboard (because they are interconnected).

When describing the characteristics of the motherboard, we refer to the processor, when considering the RAM, we also take into account the characteristics of the above elements, since they are the main "thinking" part of the computer. The operational interconnection of these components allows your iron assistant to quickly carry out the necessary operations.

Therefore, the choice of memory must be approached on the basis of these considerations of interconnection, otherwise it turns out that you have acquired a "cool" memory, but the motherboard does not support it and then lie to her dear and wait for your "finest hour" :).

To find out which processor your motherboard supports, as well as which memory module is needed for it, you need:

• refer to the site of the board manufacturer
• find, by alphanumeric marking, your model (for example, manufacturer Gigabyte GA-P55A-UD4P)
• study the manual for supported processors and the list of recommended memory modules (i.e. those manufacturers and models that are 100% compatible with your board).

To clear up all the questions, I will give a specific example (no need, don’t thank me :-)).

We go to the manufacturer's website (1) and look for the motherboard model by labeling, for simplicity we drive the data into the search (2).

Note
Marking (motherboard model / manufacturer), for example, can be found through the DirectX diagnostic tool (called by the "Win + R" command line key combination and entering dxdiag, then we remember the lines - PC manufacturer and model).

Click on the links "Supported processors" (1) and "List of recommended memory modules" (2). For memory, download this list (in pdf format) by clicking on the appropriate link.

Determine the type of processor (1) (let's say Core i5-760) and the memory model (2) (let's say Kingston KHX1600C9D3K2 / 4G).

That's all, nothing complicated!

Now we know that our motherboard and processor will not conflict with this memory, and with the combination of these three components, you can squeeze out the cherished 10-15% increase in overall computer performance and avoid, say, terrible and terrible ones.

Now let's go directly to the technical parameters themselves.

Memory type

First of all, you need to decide on the type of memory. At the time of this writing, the market is dominated by third-generation DDR (double-data-rate) memory modules, or DDR3. DDR3 memory has higher clock speeds (up to 2400 megahertz), power consumption reduced by about 30-40% (compared to DDR2) and, accordingly, less heat dissipation.

However, you can still find DDR2 memory and outdated (and therefore terribly expensive in some places) DDR1 memory. All these three types are completely incompatible with each other both in electrical parameters (DDR3 has less voltage) and physical (see image).

This is done so that even if you made the wrong choice, you would not be able to insert an incompatible memory strip (although some are very diligent, and therefore it happens .. uh .. boom! :)).

Note
It is worth mentioning the new type of DDR4 memory, which differs from previous generations in higher frequency characteristics and lower voltage. It supports frequencies from 2133 to 4266 MHz and is expected to go into mass production in mid-2012. Also, do not confuse RAM (mentioned DDR) with video memory (namely GDDR). The latter (of the GDDR 5 type) has high frequencies, reaching 5 GHz, but so far they are used only in video cards.

Form factor

When choosing, always pay attention to the form factor - the standard that specifies the overall dimensions of the device or, in simpler terms, the type of construction of the bar itself.

DIMM (Dual Inline Memory Module, means that the contacts are located on both sides) - for desktop PCs, and SO-DIMM - for laptops (recently, laptop memory can be found in monoblocs or compact multimedia PCs).

As you can see in the picture above, they are of different sizes, so it is difficult to miss.

Bus frequency and bandwidth

The main parameters of the RAM that characterize its performance are the bus frequency and data transfer rate.

The frequency characterizes the potential of the memory bus for transferring data per unit of time, respectively, the higher it is, the more data can be transferred. The bus frequency and bandwidth depend in direct proportion to each other (for example, the memory has a 1333 MHz bus, which means theoretically it will have a bandwidth of 10600 Mb / s, and the module itself will say DDR3 1333 (PC-10600)).

The frequency is indicated as "DDR2 (3) -xxxx" or "PC2 (3) -yyyy". In the first case, "xxxx" indicates the effective memory frequency, and in the second, "yyyy" indicates the peak bandwidth. In order not to get confused, look at the table (it contains the most popular standards: DDR (1), DDR2 (2), DDR3 (3)).

Which frequency should you choose?

As mentioned above, you need to build on the capabilities that your system provides. We recommend that the frequency coincide with the frequency supported by the motherboard / processor.

For example, you plugged a DDR3-1800 module into a slot (connector) that supports a maximum of DDR3-1600, as a result the module will operate at the frequency of the slot, i.e. 1600 MHz, not using its resource in full, while failures and errors in the operation of the system are also likely. I must say that now the most common and recommended for purchase are DDR3 modules with a clock frequency of 1333 and 1600 MHz.

For a comprehensive assessment of the capabilities of the RAM, the term memory bandwidth is used. It takes into account the frequency at which data is transmitted, the width of the bus and the number of memory channels (this is a rather important parameter of the OP's performance).

Memory modes

In modern computers, motherboards support special modes of operation of RAM. It is in these modes that the speed of its operation will be the most efficient, therefore, to achieve the best performance, the modes of operation of memory modules and their correct installation should be taken into account.

What is memory mode? - this is similar to the operation of multiple CPU cores, i.e. theoretically, the speed of the memory subsystem in the dual-channel mode increases 2 times, in the three-channel mode - 3 times, respectively, and so on.

Let's take a closer look at the types of modes:

• Single chanell mode (single-channel or asymmetric) - this mode is enabled when only one memory module is installed in the system or all modules differ from each other in terms of memory size, operating frequency or manufacturer. It doesn't matter in which slots and memory to install. All memory will run at the speed of the slowest memory installed.
• Dual Mode (two-channel or balanced) - the same amount of RAM is installed in each channel (and theoretically, the maximum data transfer rate doubles). To enable dual-channel mode, memory modules are installed in pairs in 1 and 3 and / or 2 and 4 slots.
• Triple Mode (three-channel) - the same amount of RAM is installed in each of the three channels. Modules are selected in terms of speed and volume.
  To enable this mode, modules must be installed in slots 1, 3 and 5 / or 2, 4 and 6 slots. In practice, by the way, this mode is not always more productive than the two-channel mode, and sometimes even loses to it in the data transfer rate.
• Flex Mode (flexible) - allows you to increase the performance of the RAM when installing two modules of different sizes, but the same frequency of operation. As in the dual-channel mode, memory cards are installed in slots of the same name on different channels.

Usually the most common option is dual channel memory.

Note
There are motherboards on sale with support for four-channel memory operation, which, in theory, will give you maximum performance. In general, for the efficient organization of memory operation, it is necessary to install an even number of memory modules (2 or 4), and in pairs they must be of the same size and preferably from the same batch (or the same manufacturer).

Does memory size or size matter?

Another important parameter, about which they say that the more, the better, is volume. I note right away that although this is an essential characteristic, it is often credited with almost all the laurels in the difficult task of increasing the performance of a PC, which is not always true, but there is a place to be.

I wrote a few words about large amounts of memory in the post "".

For those who are too lazy to read the note itself, I will simply say that, as for me, volumes of 6 GB or more are reasonable, especially in cases of a weak disk subsystem (since memory is now worth a penny). And the reserve for the future will be good, because, as practice shows, programs and operating systems are starting to consume more and more memory.

Timings

In it, in addition to the fact that you can find out general information about the memory (Memory tab), you can also see (SPD tab) whether your "baby" is capable of overclocking, i.e. whether she is friendly with the XMP or EPP profile.

Cooling

Most of the elements in the process of the PC work quite "pretty" warm and the memory is no exception (I will not say that you can fry eggs on it, like on a video card, but it is quite possible to burn yourself :)). To remove heat from microcircuits, manufacturers equip their dies with special metal plates / radiators, cooling shrouds. In high-speed models (pre-designed for overclocking), sometimes it comes to a full-fledged separate cooling system (with a large number of all kinds of pipes and elements, as in the image).

Therefore, if you are planning, shall we say, to "heavily load" your RAM and also engage in (in the future) overclocking, think about a normal system for its cooling. Globally, even for an ordinary user, I recommend buying memory in at least some kind of heatsinks.

ECC Error Correction

Modules with such markings have on board a special controller designed to detect and correct various memory errors. In theory, such a system should increase the stability of the RAM. In practice, the difference in performance between "regular" and more expensive ECC memory is almost imperceptible. Therefore, there is no particular point in purchasing such modules on purpose. In addition, the use of ECC in memory modules can reduce the speed of its operation by 2-10%.

Actually, we finished with the parameters, but the most delicious remained as always for dessert! Well, we begin to absorb it :).

Correct memory installation after selection and purchase

It would seem that there is nothing to tell about the correct installation of the OP (it seems like everything is simple - I stuck it in, clicked and the order), but this is not entirely true and now we will study this issue with all the degree of seriousness :).

So (before installing), remember the basic rules:

• be careful
• carry out all work with the computer completely disconnected from the mains, with dry hands
• do not use excessive force - memory modules are very fragile!
• Place the system unit on a solid and stable surface.

Let's move on to the process itself.

Step 1.
First of all, open the side cover of the system unit (for a standard vertical case, this is the left cover when you look at the system unit from the front). Find the motherboard inside the box — the largest board located directly in front of you. On this board you will see a block of connectors for installing RAM modules.

Note
The number of OP slots is usually 2-6 connectors for most motherboards used in home computers. Before installing, pay attention to the video card - it may interfere with the installation of RAM. If it interferes, then temporarily dismantle it.

Step 2.
On the free slot selected for installing the RAM, unfasten the special latches on the edges.

Carefully remove the new brains (do not bend them, take them gently but firmly by the edges) from the antistatic packaging.

Note
Inside each connector there are small jumper keys, and on the contact part of the memory modules there are corresponding cutouts. Their mutual combination excludes incorrect installation of memory or installation of modules of a different type. Each type has a different location and number of slots, and, consequently, keys on the motherboard connectors (we already mentioned this when we talked about memory types).

Step 3.
Align the notch in the memory with the key in the slot on the motherboard (as shown in the image).

If you cannot match the keys on the memory strip and on the motherboard connector, then most likely you bought the wrong type of memory. Check everything again, it is better to return the purchase to the store and exchange it for the desired type of memory.

Step 4.
Insert the DIMM into the slot by pushing down on the top edge of the DIMM.

Step 5.
Press down gently until the module is fully seated in the slot and the retention clips at the edges of the slot snap into place.

Step 6.
Make sure the retaining tabs are in place and closed completely.

That's it, the memory is installed correctly! Replace the case cover and reconnect the computer to an electrical outlet. After installing new RAM, be sure to test it with special utilities to identify errors.

It is worth saying a few words about the modes of operation of the RAM.

Motherboards allow memory to work in n-channel (two / three / four) modes. For this, slots are distinguished by color and divided into pairs.

For example, in order to use the two-channel operating mode of the OP, it is necessary that the modules (of the same frequency / volume) be inserted into the connectors of the same name (in the same color, 1 and 3) from different channels (see image).

This procedure allows you to achieve a performance increase of 5-10% (in comparison with the single-channel mode).

Everybody is here!

By following these installation instructions, you will not only easily install the memory (even if you have never done it before) in the "right" place, but also get the maximum performance from it in the system.

User's Choice Reminder

Since we got a lot of information, let's highlight the main points that you need to learn:

• Find out in advance the type of memory supported (recommended) by the manufacturer
• Install memory modules with the same timings / volume / frequency and from the same manufacturer. Ideally, purchase a kit - these are two modules with the same characteristics from the same manufacturer, already tested in collaboration
• The RAM bus bandwidth must match the processor bus bandwidth
• To achieve the best performance, consider the modes of operation of the modules and their correct installation.
• Look for memory with minimum standard timings (less -> better)
• Choose the amount of memory based on the tasks solved by the PC and the type of operating system
• Choose well-known (proven) manufacturers, for example: OCZ, Kingston, Corsair, etc.
  
• The overclocking potential of the memory directly depends on the chips on which it is produced. Therefore, make sure that the memory was made by a well-known manufacturer, then it is most likely that the chips will provide more reliable power supply, will have greater noise immunity, which will have a beneficial effect on memory operation in abnormal modes.
• If you plan to overclock the system or want to get maximum performance (for example, build a gaming PC), then you should pay attention to a special overclocking memory with enhanced cooling.

Based on this information, you will be able to correctly choose the appropriate memory module, which will take care that the birthmark keeps (and does not drop) a high performance bar for a long time.

I would also like to say that if you hope that somewhere between the lines we will say a few more words about overclocking, then do not hope (:)), because a separate (even more delicious) article will be devoted to this issue, which will contain all the subtleties of overclocking. and "squeeze" the maximum out of my "brains". However, this is a completely different story ..

Where is the best place to buy RAM?

Days to change the product without any questions, and even in case of warranty problems, the store will take your side and help you solve any problems. The author of the site has been using it for at least 10 years (since the days when they were part of Ultra Electoronics), which he advises you;

, is one of the oldest stores on the market, as the company has existed for about 20 years. Decent selection, average prices and one of the most user-friendly sites. All in all, it's a pleasure to work with.

The choice is traditionally yours. Of course, nobody canceled Yandex.Market's all sorts of things, but from good stores I would recommend just these, and not some MVideo and other large networks (which are often not just expensive, but flawed in terms of quality of service, warranty etc.).

Afterword

I hope that this material will take its rightful place on the shelf with the luggage of your "iron knowledge" and more than once (but two or even three :)) will help with advice in the difficult matter of buying a "thinking filling" for a computer fellow.

Stay tuned to our IT wave and you will learn a lot more interesting things. As always, if you have something to say, then the comments are patiently waiting for their turn.

PS: In addition to dancing with tambourines over the RAM in order to increase the performance of the computer, you can use another very good tool - the paging file. You can learn how to create / configure it correctly from the note located at.

PS 2: Thanks to team member 25 FRAME for the existence of this article

- Faster, even faster, well, speed up, please, at least a little, otherwise I’m now ...

- I can't, dear Gamer, because I have reached my maximum clock frequency.

Something like this might look like a dialogue and Gamer, who counts every fraction of a second.

The clock frequency of the random access memory (RAM, RAM) is the second most important parameter after the volume. The higher it is, the faster the data exchange between the processor and RAM occurs, the faster the computer works. Low clock speeds can be a bottleneck in resource-intensive games and programs. And if you do not want to beg the capricious piece of iron to add a little speed every time, always pay attention to this characteristic when buying. Today we'll talk about how to find out the frequency of RAM from the description in store catalogs, as well as the one installed on your PC.

How to understand what kind of "beast" the store offers

In the description of RAM modules on the sites of online stores, sometimes not all are indicated, but only individual speed characteristics. For instance:

• DDR3, 12800 MB / s.
• DDR3, PC12800.
• DDR3, 800 MHz (1600 MHz).
• DDR3, 1600 MHz.

Some might think that this example is about four different slats. In fact, this is how one and the same RAM module with an effective frequency of 1600 MHz can be described! And all these numbers indirectly or directly indicate her.

In order not to get confused anymore, let's figure out what they mean:

• 12800 Mb / s Is the memory bandwidth, an indicator obtained by multiplying the effective frequency (1600 MHz) by the width of the bus of one channel (64 bits or 8 bytes). Bandwidth describes the maximum amount of information that a RAM module can transmit in one clock cycle. How to determine the effective frequency from it, I think, is clear: you need to divide 12800 by 8.
• PC12800 or PC3-12800- another designation of the bandwidth of the RAM module. By the way, a set of two strips, intended for use in dual-channel mode, has 2 times higher bandwidth, so its label may have the value PC25600 or PC3-25600.
• 800 MHz (1600 MHz)- two values, the first of which indicates the frequency of the memory bus itself, and the second - twice as large - to its effective frequency. How do the indicators differ? Computers, as you know, use DDR-type RAM - with a double data transfer rate without increasing the number of bus cycles, that is, not one, but two conditional pieces of information are transferred through it in 1 clock cycle. Therefore, the main indicator is considered to be the effective clock frequency (in this example - 1600 MHz).

The screenshot below shows a description of the speed characteristics of the RAM from the catalogs of three computer stores. As you can see, all sellers designate them in their own way.

Different RAM modules within the same generation - DDR, DDR2, DDR3 or DDR4 - have different frequency characteristics. So, the most common DDR3 RAM for 2017 is released with frequencies of 800, 1066, 1333, 1600, 1866, 2133 and 2400 MHz. Sometimes it is denoted that way: DDR3-1333, DDR3-1866, etc. And this is convenient.

Not only the RAM has its own effective frequency, but also the device that controls it - the memory controller. In modern computer systems, starting with the Sandy Bridge generation, it is part of the processor. In older ones, they are included in the components of the north bridge of the motherboard.

Almost all RAM can operate at lower clock rates than indicated in the specifications. RAM modules with different frequencies, provided that the other parameters are similar, are compatible with each other, but they are capable of functioning only in single-channel mode.

If the computer has several strips of RAM with different frequency characteristics, the memory subsystem will exchange data at the speed of the slowest link (except for devices supporting XMP technology). So, if the frequency of the controller is 1333 MHz, one of the bars is 1066 MHz, and the other is 1600 MHz, the transmission will go at a speed of 1066 MHz.

How to find out the frequency of the RAM on the computer

Before learning how to determine the frequency indicators of RAM on a PC, let's figure out how the computer itself recognizes them. It reads the information written in the SPD chip, which is equipped with each separate RAM strip. What this microcircuit looks like is shown in the photo below.

SPD data can also be read by programs, For example, the well-known utility CPU-Z, one of the sections of which is called “ SPD". In the screenshot below, we see the already familiar characteristics of the speed of the RAM bar (the field “ MaxBandwidth") - PC3-12800 (800 MHz). To find out its effective frequency, it is enough to divide 12800 by 8 or 800 multiply by 2. In my example, this figure is 1600 MHz.

However, in CPU-Z there is one more section - " Memory", And in it - the parameter" DRAMFrequency"Equal to 665.1 MHz. This is, as you probably guessed, the actual data, that is, the frequency mode in which the RAM actually operates. If we multiply 665.1 by 2, we get 1330.2 MHz - a value close to 1333 - the frequency at which this laptop's memory controller operates.

In addition to CPU-Z, other applications used to recognize and monitor PC hardware show similar data. Below are screenshots of the free utility HWiNFO32 / 64 :

And paid, but beloved by Russian users AIDA64 :

Where and what to watch, I think, is clear.

Finally, the last way to find out the frequency of the RAM is to read the label glued to the strip itself.

If you read the article from the beginning, it will not be difficult for you to find the information you need in these lines. In the example shown above, the metric of interest is 1600 MHz and is hidden in the word “PC3L-12800s”.

This tab describes the data SPD- a mechanism used to determine the presence and characteristics of memory modules. Stands for serial presence detect, sequential determination of availability. The word serial indicates the type of bus used in this case, I2C - it is just serial. Tire I2C included in SMBus, developed by Intel, so if you disable the detection of devices on the SMBus in CPU-Z, then SPD data will not be displayed. If you look at the memory module, you can see a small microcircuit, different from memory chips, which has eight legs. This is the so-called SPD chip. In fact, this is an ordinary "flash drive" - ​​a flash memory chip similar to those stored in the BIOS of a motherboard and video cards (and other various peripherals).

Almost all motherboards set timings and frequencies based on SPD data, so errors in this data can lead to the system being unable to start. Problems are especially common with modules designed for enthusiasts. Sometimes the frequencies and timings hardwired into the SPD are designed for use at increased voltage, which leads to the impossibility of booting at standard voltage and you need to find a regular module, set the desired voltage in the BIOS and then plug in the original modules. At least Corsair had this problem. Another example is when the manufacturer writes on the sticker the frequencies and timings and voltages at which the memory can be used, but in order to boot, he prescribes safe frequencies in the SPD, greatly overestimated, or overestimated timings. And then newbies have questions, they say, why did you buy DDR2-1066 memory, and it is defined as DDR2-800?

And now, in fact, the data that we can see on this tab. First group, Memory slot selection:

• combo box to select a module. Allows you to select the memory module for which SPD information is displayed.
• on the right is a field with the name of the memory type, in our case - DDR2.
• Module Size- module size in megabytes.
• Max. Bandwith- maximum throughput. In this case, PC2 stands for DDR2 memory, and the number after that stands for maximum bandwidth in megabytes. The real frequency of the DDR bus is written in brackets. The bandwidth is calculated using the formula: Freq * 64 * 2/8, where 64 is the memory bus width in bits (for all modules SDRAM it is equal to 64 bits), 2 - means DDR technology, which doubles the bandwidth, and division by 8 converts bits to bytes (there are 8 bits in 1 byte). So, for DDR2-800 with a real frequency of 400MHz, we get: 400 * 64 * 2/8 = 6400MB / s, as shown by CPU-Z.
• Manufacturer- the name of the manufacturer of the memory module. Usually not filled Noname(unnamed) manufacturers.
• Part Number- batch number. Similarly, not filled Noname.
• Serial Number- serial number of the module. Unnamed manufacturers sew one firmware, because the concept of serial production does not exist at all.
• Correction- the module has error correction. It is not found on ordinary memory, and it is easy to distinguish such a module by the "extra" memory chip. If a normal module has 4 or 8 chips on one side, then this one has 5 or 9. It is located in the middle. On some modules, you can see the space on the board for this chip.
• Registered- the presence of register memory. Enthusiasts are not interested.
• Buffered- the presence of buffered memory - again, not of interest to enthusiasts.
• SPD Ext.- availability of SPD extensions. SPD is developed by the organization JEDEC for the adoption of memory standards. But the company NVIDIA proposed to use bytes unused by the standard (and there are a lot of them) for high-speed profiles, where they will not only prescribe the main and additional timings, but also the voltage. She called her standard EPP - enhanced performance profile(improved performance profile). Following her Intel added to its chipsets support for similar profiles with the name XMP - extreme memory profile(extreme memory profile). Profiles have been made for beginners who cannot overclock and set the necessary settings themselves, so they are not recommended for enthusiasts. The memory module supports either EPP or XMP, but the point is not so much that both algorithms use contiguous bytes. The main reason is, of course, political. Remembrance must receive the blessing of either one company or another to proclaim support for the profile. It is technically possible to support both, but of course it will not be approved.
• Week / Year - week and year of issue.

The next group is Timings Table- Timing table for different frequencies. Column labels indicate the number of the table created according to the standard JEDEC, or the profile EPP / XMP if available.

• Frequency- memory frequency. As mentioned, may differ from what is written on the label, which is usually normal if the memory can operate at the frequency declared by the manufacturer.
• CAS # Latency- the minimum time between sending a read command ( CAS #) and the start of data transfer (read delay).
• RAS # to CAS #- the time required to activate a bank row, or the minimum time between the signal to select the row (RAS #) and the signal to select the column ( CAS #).
• RAS # Precharge- the time required to precharge the bank (precharge). In other words, the minimum time to close a line, after which a new bank line can be activated.
• tRAS- the minimum time the row is active, that is, the minimum time between the activation of the row (its opening) and the issuance of the command to precharge (the beginning of the closing of the row).
• tRC- the minimum time between the activation of the lines of one bank. Is a combination of timings tRAS+tRP- the minimum time the line is active and the time it was closed (after which you can open a new one).
• Command Rate- the time required for the controller to decode commands and addresses. Otherwise, the minimum time between two commands. Used only in advanced profiles.
• Voltage- used voltage. JEDEC uses only the standard value, so this field will differ only in advanced profiles.