home › Google Chrome. › RAM DDR2 characteristics. How to distinguish SIMM, DIMM, DDR, DDR2, DDR3 memory types. Type of RAM

RAM DDR2 characteristics. How to distinguish SIMM, DIMM, DDR, DDR2, DDR3 memory types. Type of RAM

RAM is used to temporarily storing the data required for the operating system and all programs. Runifying memory should be enough if it is not enough, the computer begins to slow down.

The board with memory chips is called the memory module (or bar). The memory for a laptop, in addition to the size of the planks, nothing is different from memory for the computer, so when you select, follow the same recommendations.

For an office computer, a single DDR4 plan4 is sufficient to 4 GB with a frequency of 2400 or 2666 MHz (it is almost the same).
RAM MEMORY CRUCIAL CT4G4DFS824A

For a multimedia computer (movies, simple games), it is better to take two DDR4 strips with a frequency of 2666 MHz to 4 GB, then the memory will work in a faster two-channel mode.
RAM BALLISTIX BLS2C4G4D240FSB

For a mid-class gaming computer, you can take one DDR4 bar4 to 8 GB with a frequency of 2666 MHz so that in the future you can add one more and better if it is the running model easier.
RAM CRUCIAL CT8G4DFS824A

And for a powerful gaming or professional PC, you need to immediately take a set of 2 DDR4 operators of 8 GB, while the frequency of 2666 MHz will be quite enough.

2. How much memory you need

For an office computer designed to work with documents and accessing the Internet, with the head of a single memory strip on 4 GB.

For a multimedia computer that can be used to view the video in high quality And the undemanding games, it is enough 8 GB of memory.

For a mid-class gaming computer, a minimum option is 8 GB of RAM.

For a powerful gaming or professional computer, 16 GB of memory is necessary.

A greater memory capacity may only be needed for very demanding. professional programs And normal users do not need.

Memory capacity for old PC

If you decide to increase the amount of memory on the old computer, then you will note that 32-bit versions of Windows do not support more than 3 GB random access memory. That is, if you install 4 GB of RAM, then operating system Will see and use only 3 GB.

As for the 64-bit versions of Windows, they will be able to use all the installed memory, but if you have an old computer or there is an old printer, then they may not be drivers for these operating systems. In this case, before purchasing memory, set the 64-bit bit windows version And check if you work. I also recommend to look at the manufacturer's website of the motherboard and see what volume of modules and the total amount of memory it supports.

Note that the 64-bit operating systems spend 2 times more memory, for example, Windows 7 x64 takes about 800 MB under its needs. Therefore, 2 GB of memory for such a system will be little, preferably at least 4 GB.

Practice shows that modern Windows 7.8.10 operating systems are completely disclosed at a memory of 8 GB. The system becomes more responsive, the program opens faster, and jerks (friezes) disappear in games.

3. Memory types

Modern memory has a DDR SDRAM type and is constantly improving. So the DDR and DDR2 memory is already obsolete and can only be used on old computers. DDR3 memory is no longer expedient to use on new PCs, it came to replace the faster and promising DDR4.

Note that the selected memory type should support the processor and motherboard.

Also new processors, for compatibility considerations, can support DDR3L memory, which differs from the usual DDR3 reduced voltage from 1.5 to 1.35 V. Such processors will be able to work with normal DDR3 memory, if you already have it, but processor manufacturers do not recommend this - the excessive degradation of memory controllers designed for DDR4 with even more low voltage 1.2 V.

Memory type for old PC

Outdated DDR2 memory stands several times more expensive modern memory. Planck DDR2 on 2 GB stands 2 times more expensive, and a DDR2 plan2 on 4 GB is 4 times more expensive than a DDR3 or DDR4 strip.

Therefore, if you want to significantly increase memory on the old computer, then a more optimal option will be the transition to a more advanced platform with the motherboard and if the processor is needed to support DDR4 memory.

Calculate how much it will cost you, it is possible to sell an old motherboard with an old motherboard and acquire new, let not the most expensive, but more modern components.

Motherboard connectors for memory installation are called slots.

Each type of memory (DDR, DDR2, DDR3, DDR4) corresponds to its slot. DDR3 memory can only be installed in the motherboard with DDR3, DDR4 slots - with DDR4 slots. Motherboards supporting the old DDR2 memory no longer produce.

5. Memory characteristics

The main characteristics of the memory on which its speed depends is the frequency and timings. The speed of memory does not have such a strong influence on the overall performance of the computer as a processor. However, it is often possible to purchase a faster memory not much more expensive. Fast memory We need primarily for powerful professional computers.

5.1. Memory frequency

The frequency has the greatest value to the speed of memory. But before purchasing it, you must make sure that the processor and motherboard also support the necessary frequency. Otherwise, the actual frequency of memory will be lower and you will simply overpay for not being used.

Cheap motherboards support a lower maximum memory frequency, for example, for DDR4 is 2400 MHz. Maternally and high-class motherboards can support higher frequency memory (3400-3600 MHz).

But with the processors the case is different. Old processors with DDR3 memory support can support memory with a maximum frequency of 1333, 1600 or 1866 MHz (depending on the model). For modern processors with DDR4 memory support, the maximum supported memory frequency can be 2400 MHz or higher.

Intel processors of the 6th generation and higher, as well as processors AMD Ryzen. Support DDR4 memory with a frequency of 2400 MHz or higher. At the same time in their model row There are not only powerful expensive processors, but also the processors of the middle and budget class. Thus, you can assemble a computer on the most modern platform with an inexpensive processor and DDR4 memory, and in the future, change the processor and get the highest performance.

The main one is the memory of DDR4 2400 MHz, which is supported by the most modern processors, motherboards and costs as much as DDR4 2133 MHz. Therefore, to acquire DDR4 memory with a frequency of 2133 MHz today does not make sense.

What frequency of memory is supported by one or another processor can be found on the sites of manufacturers:

By the model number or serial number it is very easy to find all the characteristics of any processor on the site:

Or simply enter the model number in the search engine google system or Yandex (for example, "Ryzen 7 1800x").

5.2. High frequency memory

Now I want to touch on another interesting point. On sale you can meet the RAM of much higher frequency, which supports any modern processor (3000-3600 MHz and above). Accordingly, many users are wondering how can it be?

It's all about the technology developed by Intel, Extreme Memory Profile (XMP). XMP allows memory to work at a higher frequency than officially supports the processor. XMP must support both memory itself and the motherboard. High frequency memory simply cannot exist without supporting this technology, but not all motherboards can boast its support. Basically, it is more expensive models above the middle class.

The essence of XMP technology is that the motherboard automatically increases the frequency of the memory bus, thanks to which the memory begins to work at its higher frequency.

AMD has a similar technology called AMD Memory Profile (AMP), which was supported by old motherboards for AMD processors. These motherboards usually supported XMP modules.

Purchase more expensive memory with a very high frequency and motherboard with XMP support It makes sense for very powerful professional computers equipped with a top processor. In the middle-class computer, this will be thrown on the wind money, since everything will be paid to the performance of other components.

In games, the frequency of memory has a slight effect and there is no particular sense, it will be enough to take on a 2400 MHz, or for 2666 MHz if the price difference is small.

For professional applications, you can take memory with the frequency higher - 2666 MHz or if you want and allow funds for 3000 MHz. The difference in performance here is more than in games, but not cardinal, so there is no sense to drive with the frequency of memory.

Once again I remind you that your motherboard must support the memory of the required frequency. In addition, sometimes Intel processors begin to work unstable at a memory frequency above 3000 MHz, and Ryzen this limit is about 2900 MHz.

Timins are called delays between read / write / copy data in RAM. Accordingly, than these delays less, the better. But the timings have a much smaller impact on the speed of memory, than its frequency.

The main timings, which are indicated in the characteristics of the memory modules of only 4.

Of these, the most important is the first digit, which is called latency (CL).

Typical latency for DDR3 memory 1333 MHz - Cl 9, for DDR3 memory with higher frequency - Cl 11.

Typical latency for DDR4 2133 MHz - Cl 15, for DDR4 memory with higher frequency - CL 16.

It is not necessary to purchase memory with latency higher than specified, as it speaks about the total low level of its technical characteristics.

Usually, memory with lower timings is more expensive, but if the difference in price is not significant, then the preference is followed to give memory with lower latency.

5.4. Supply voltage

Memory may have different supply voltage. It can be both standard (generally accepted for a specific type of memory) and elevated (for enthusiasts) or vice versa reduced.

This is especially important if you want to add memory to a computer or laptop. In this case, the voltage of new slats should be the same as the available. Otherwise, problems are possible, since most motherboards cannot set different voltages for different modules.

If the voltage is displayed on a strip with a lower voltage, then the other may not be enough power and the system will not work stably. If the voltage is displayed on a strip with a higher voltage, then the memory calculated for fewer voltage can fail.

If you are collecting new computer, it is not so important, but to avoid possible problems Compatibility S. motherboard and replacing or expansion of memory in the future, it is better to choose a plank with standard supply voltage.

Memory, depending on type, has the following standard supply voltages:

DDR - 2.5 in
DDR2 - 1.8 in
DDR3 - 1.5 in
DDR3L - 1.35 V
DDR4 - 1.2 in

I think you drew attention to the fact that the list is DDR3L memory. This is not a new type of memory, but the usual DDR3, but with reduced power voltage (LOW). Such a memory is needed for intel processors The 6th generation and above that are supported by both the memory DDR4 and DDR3. But it is better in this case to collect the system on the new DDR4 memory.

6. Marking of memory modules

Memory modules are marked depending on the type of memory and its frequency. The labeling of the DDR memory modules starts with PC, then there is a digit that denotes generation and speed in megabytes per second (MB / s).

In such marking, it is inconvenient to navigate, it is enough to know the type of memory (DDR, DDR2, DDR3, DDR4), its frequency and latency. But sometimes, for example on ad sites, you can see the marking rewritten from the plank. Therefore, so that you can navigate in this case, I will give a classic labeling, with a type of memory, its frequency and typical latency.

DDR - outdated

PC-2100 (DDR 266 MHz) - CL 2.5
PC-2700 (DDR 333 MHz) - CL 2.5
PC-3200 (DDR 400 MHz) - CL 2.5

DDR2 - outdated

PC2-4200 (DDR2 533 MHz) - Cl 5
PC2-5300 (DDR2 667 MHz) - Cl 5
PC2-6400 (DDR2 800 MHz) - Cl 5
PC2-8500 (DDR2 1066 MHz) - Cl 5

DDR3 - Obsolete

PC3-10600 (DDR3 1333 MHz) - Cl 9
PC3-12800 (DDR3 1600 MHz) - Cl 11
PC3-14400 (DDR3 1866 MHz) - Cl 11
PC3-16000 (DDR3 2000 MHz) - Cl 11

PC4-17000 (DDR4 2133 MHz) - Cl 15
PC4-19200 (DDR4 2400 MHz) - Cl 16
PC4-21300 (DDR4 2666 MHz) - CL 16
PC4-24000 (DDR4 3000 MHz) - CL 16
PC4-25600 (DDR4 3200 MHz) - Cl 16

DDR3 and DDR4 memory can have a higher frequency, but only top processors and more expensive motherboards can work with it.

7. Construction of memory modules

Memory bar can be one-sided, double-sided, with radiators or without.

7.1. Placing chipov

Chips on memory modules can be placed on one side of the board (one-sided) and on both sides (double-sided).

It does not matter if you acquire memory for a new computer. If you want to add memory to the old PC, it is desirable that the location of chips on the new bar is the same as on the old one. This will help avoid compatibility issues and increase the probability of memory in two-channel mode, which we will talk about in this article.

Now you can find many memory modules with aluminum radiators of various colors and shapes.

The presence of radiators can be justified at the memory of DDR3 with a high frequency (1866 MHz or more), as it warms it harder. In this case, ventilation should be well organized in the case.

The modern DDR4 operative with a frequency of 2400, 2666 MHz is practically not heated and radiators on it will be purely decorative. They may even interfere, because after a while they score dust, which is difficult to clean out of them. In addition, this memory will be somewhat more expensive. So, if you want, this can be saved, for example, taking excellent CRUCIAL memory for 2400 MHz without radiators.

Memory with a frequency of 3000 MHz has also increased supply voltage, but also heats up not much and in any case there will be radiators.

8. Memory for laptops

The memory for laptops differs from memory for stationary computers only the size of the memory module and marked SO-DIMM DDR. As well as for stationary computers, laptop memory has types DDR, DDR2, DDR3, DDR3L, DDR4.

In frequency, timings and power voltage memory for laptops does not differ from memory for computers. But laptops are equipped with only 1 or 2 memory slots and have more stringent limitations of the maximum volume. Be sure to specify these parameters before selecting the memory for specific model laptop.

9. Memory Modes

Memory can work in single channel (SINGLE CHANNEL), two-channel (Dual Channel), three-channel (Triple Channel) or four-channel mode (Quad Channel).

In one-channel mode, data recording occurs sequentially into each module. In multichannel modes, the data record occurs in parallel to all modules, which leads to a significant increase in the speed of the memory subsystem.

One-channel mode of memory operation is limited only hopelessly outdated motherboards with DDR memory and the first models with DDR2.

All modern motherboards support two-channel memory mode, and three-channel and four-channel mode support only some single models of very expensive motherboards.

The main condition for the operation of the two-channel mode is the presence of 2 or 4 memory schedules. For a three-channel mode, you need 3 or 6 memory schedules, and for four-channel 4 or 8 slats.

It is desirable that all memory modules are the same. Otherwise, the work in two-channel mode is not guaranteed.

If you want to add memory to the old computer and your motherboard supports a two-channel mode, try to choose the most identical to all the parameters of the bar. It is best to sell old and buy 2 new identical planks.

In modern computers, memory controllers were transferred from the motherboard to the processor. Now it is not so important that the memory modules are the same, since the processor in most cases can still activate the two-channel mode. This means that if you want to add memory in the future modern computerThis will not necessarily look for exactly the same module, it is enough to choose the most similar on the characteristics. But still I recommend that the memory modules were the same. It will give you a guarantee of its fast and stable work.

With the transfer of memory controllers to the processor, 2 more two-channel memory modes - Ganged (paired) and unganged (unpaired) appeared. If the memory modules are the same, the processor can work with them in Ganged mode, as before. If the modules differ in terms of characteristics, then the processor can activate the UnganGed mode to eliminate the disks in memory. In general, the speed of memory in these modes is almost the same and has no difference.

The only disadvantage of the two-channel regime is that several memory modules are more expensive than one of the same volume. But if you are not very constrained in the means, then buy 2 planks, the speed of memory will be significantly higher.

If you need, say 16 GB RAM, but you can not allow it to yourself, you can purchase one bar on 8 GB to add another same in the future. But it is still better to acquire two identical strips at once, since then it may not work out to find the same and you will come across the problem of compatibility.

10. Memory module manufacturers

One of better relationships The price / quality for today possesses the memory of the immaculately proven brand Crucial, which has modules from budget to Gamers (Ballistix).

Along with him, the Corsair brand enjoyed by the well-deserved popularity, whose memory is somewhat more expensive.

As an inexpensive, but high-quality alternative, especially recommended by the Polish Brand GOODRAM, which has a low timing planks for low price (Play Line).

For an inexpensive office computer, it will be enough simple and reliable memory of the production of AMD or Transcend. They have greatly proven themselves and practically no problems with them.

In general, Korean companies Hynix and Samsung are considered leaders in memory production. But now the modules of these brands are massively produced on cheap Chinese factories and there are a lot of fakes among them. Therefore, I do not recommend purchasing the memory of these brands.

The exception can be the memory modules of the Hynix Original and Samsung Original, which are manufactured in Korea. These planks are usually blue, their quality is considered better than in China made in China and the warranty is somewhat higher. But in speed characteristics, they are inferior to memory with lower timings of other high-quality brands.

Well, for enthusiasts and lovers of moding there are affordable overclocker brands GEIL, G.SKILL, TEAM. Their memory is distinguished by low timings, high acceleration potential, unusual external species And it costs a little cheaper Corsair brand spinned.

The sale also has a large range of memory modules from a very popular Kingston manufacturer. The memory sold under the Kingston budget brand has never been different. But they have a top HYPERX series, which is well-deserved, which can be recommended for the acquisition, however, the price for it is often overestimated.

11. Memory packaging

It is better to acquire memory in individual packaging.

It is usually higher than a higher quality and the likelihood of damage during transportation is significantly lower than the memory that comes without packaging.

12. Increase memory

If you plan to add memory to an existing computer or laptop, first find out what maximum volume of planks and the total memory supports your motherboard or laptop.

Also specify how many slots for memory on the motherboard or in a laptop, how many of them are occupied and which planks are installed in them. It is better to do it visually. Open the housing, remove the memory bar, consider them and rewrite all the characteristics (or make a photo).

If for some reason you do not want to climb into the case, then you can see the memory parameters in the program on the SPD tab. Thus, you will not recognize a one-sided strap or double-sided, but you can find out the memory characteristics if there are no stickers on the bar.

There is a basic and efficient memory frequency. The CPU-Z program and many similar shows the base frequency, it must be multiplied by 2.

After you learn to what volume can you increase the memory, how many free slots and what memory you have installed, you can start exploring memory increases.

If all the memory slots are occupied, then the only possibility of increasing memory remains replacing existing planks for new larger volume. And the old planks can be sold on the announcement website or pass on exchange to a computer shop when buying new ones.

If there are free slots, you can add to the already existing memory straps new. It is desirable that new planks are as close as possible according to the characteristics already installed. In this case, you can avoid various compatibility issues and increase the chances of that memory will work in two-channel mode. For this, the following conditions must be followed, in importance.

The type of memory must match (DDR, DDR2, DDR3, DDR3L, DDR4).
The supply voltage of all slats should be the same.
All planks must be one-sided or double-sided.
The frequency of all slats should coincide.
All planks must be the same volume (for a two-channel mode).
The number of slats should be even: 2, 4 (for two-channel mode).
It is desirable to coincide latency (CL).
It is desirable that the planks were the same manufacturer.

The easiest way to start a choice from the manufacturer. Choose in the online store directory planks of the same manufacturer, volume and frequency, as you have installed. Make sure that the supply voltage coincides and check the consultant one-sided or double-sided. If there is still a coincidence and latency, it is generally good.

If you failed to find similar by the characteristics of the plank of the same manufacturer, then choose all others from the list of recommended. Then, look for the planks of the desired volume and frequency, check the supply voltage and specify one-sided or double-sided. If you failed to find similar plates, then look in another store, directory or on the list of ads.

Is always the best way It is to sell all the old memory and buy 2 new identical planks. If the motherboard does not support the planks of the desired volume, you may have to buy 4 identical planks.

13. Setting up filters in the online store

Go to the "RAM" section on the seller's website.
Select Recommended Manufacturers.
Select the form factor (DIMM - PC, SO-DIMM - laptop).
Select the type of memory (DDR3, DDR3L, DDR4).
Select the required volume of the slats (2, 4, 8 GB).
Select the frequency supported by the processor (1600, 1866, 2133, 2400 MHz).
If your motherboard supports XMP, add a higher frequency memory to select (2666, 3000 MHz).
Sort sort the price.
Consistently view all positions starting with cheaper.
Select a few schedule suitable frequency.
If the price difference is acceptable for you, take the bar with a greater frequency and less latency (CL).

Thus, you will get an optimal price / quality ratio / speed memory for the minimum possible cost.

14. Links

RAM RAM CORSAIR CMK16GX4M2A2400C16
RAM RAM CORSAIR CMK8GX4M2A2400C16
RAM MEMORY CRUCIAL CT2K4G4DFS824A

Publication date:

25.06.2009

As you know, the RAM invests a greater component in the performance of the computer. And it is clear that users try to increase the amount of RAM at the maximum.
If about 2-3 years ago, there were literally several types of memory modules, now they are much more. And it became more difficult to understand them.

In this article, we will look at various designations in the marking of memory modules so that you are easier for them to navigate.

To begin with, we introduce a number of terms, which we will need to understand the article:

planck ("Dice") - memory module, printed circuit board with memory chips on board installed in the memory slot;
one-sided plank - a memory plan, in which the memory chips are located with 1 sides of the module.
a double-sided strap is a memory plan, which has a memory chip located on both sides of the module.
RAM (Random Access Memory, RAM) - Common Access Memory, Simply put - RAM. This is an energy-dependent memory, the contents of which is lost in the absence of nutrition.
SDRAM (Synchronous Dynamic RAM) - Synchronous Dynamic RAM: All Modern Memory Modules have exactly such a device, that is, require constant synchronization and updating content.

Consider marking

4096MB (2x2048MB) DIMM DDR2 PC2-8500 CORSAIR XMS2 C5 Box
1024MB SO-DIMM DDR2 PC6400 OCZ OCZ2M8001G (5-5-5-15) Retail

Volume

The first designation in the row is the amount of memory modules. In particular, in the first case it is 4 GB, and in the second - 1 GB. True, 4 GB in this case is implemented not one memory bar, but two. This is the so-called Kit of 2 - a set of two planks. Typically, such sets are bought to install the planks in two-channel mode into parallel slots. The fact that they have the same parameters will improve their compatibility, which favorably affects stability.

Type of shell

DIMM / SO-DIMM is the type of memory bar case. All modern memory modules are available in one of the two specified design versions.
Dimm. (Dual in-Line Memory Module) - a module that contacts are located in a row on both sides of the module.
The memory of the DDR SDRAM type is available in the form of 184-pin DIMM modules, and 240-contact planks are available for DDR2 SDRAM memory.

In laptops used memory modules smaller dimensions, called SO-DIMM. (Small Outline DIMM).

Memory type

The type of memory is an architecture on which the memory chips themselves are organized. It affects everything specifications Memory - productivity, frequency, voltage nutrition, etc.

On the this moment Used 3 types of memory: DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM. Of these, DDR3 is the most productive, least consuming energy.

Data frequencies for memory types:

DDR: 200-400 MHz
DDR2: 533-1200 MHz
DDR3: 800-2400 MHz

The number indicated after the type of memory - and is frequency: DDR400, DDR2-800.

All types of memory modules are characterized by supply voltage and connectors and do not allow to be inserted into each other.

The frequency of data transmission characterizes the potential of the data bus to transmit data per unit of time: the greater the frequency, the more data can be transmitted.

However, there are still factors, such as the number of memory channels, the discharge of the memory bus. They also affect the performance of memory subsystems.

For a comprehensive assessment of RAM features, the term memory bandwidth is used. It takes into account the frequency on which the data and the battery are transmitted and the number of memory channels.

Bandwidth (B) \u003d Frequency (F) X Bigness Tire Bar (C) X Channel Number (K)

For example, when using the DDR400 400 MHz memory and a two-channel memory controller, bandwidth will be:
(400 MHz x 64 Bit X 2) / 8 bits \u003d 6400 MB / s

On 8 we divided to translate Mbit / s to MB / s (in 1 bate 8 bits).

Memory Module Speed \u200b\u200bStandard

In the designation to facilitate understanding the speed of the module, the standard is also indicated bandwidth Memory. It just shows what bandwidth has a module.

All these standards begin with the PC letters and then go numbers indicating the memory bandwidth in MBs per second.

Module name	Tire frequency	Chip type
PC2-3200.	200 MHz	DDR2-400	3200 MB / s or 3.2 GB / s
PC2-4200.	266 MHz	DDR2-533	4200 MB / s or 4.2 GB / s
PC2-5300	333 MHz	DDR2-667	5300 MB / s or 5.3 GB / s 1
PC2-5400	337 MHz	DDR2-675	5400 MB / s or 5.4 GB / s
PC2-5600	350 MHz	DDR2-700	5600 MB / s or 5.6 GB / s
PC2-5700	355 MHz	DDR2-711	5700 MB / s or 5.7 GB / s
PC2-6000	375 MHz	DDR2-750	6000 MB / s or 6.0 GB / s
PC2-6400.	400 MHz	DDR2-800	6400 MB / s or 6.4 GB / s
PC2-7100	444 MHz	DDR2-888.	7100 MB / s or 7.1 GB / s
PC2-7200	450 MHz	DDR2-900	7200 MB / s or 7.2 GB / s
PC2-8000	500 MHz	DDR2-1000	8000 MB / s or 8.0 GB / s
PC2-8500	533 MHz	DDR2-1066.	8500 MB / s or 8.5 GB / s
PC2-9200.	575 MHz	DDR2-1150	9200 MB / s or 9.2 GB / s
PC2-9600.	600 MHz	DDR2-1200	9600 MB / s or 9.6 GB / s

Memory type	Memory frequency	Cycle time	Tire frequency	Data transmission per second	Name standard	Peak data transfer rate
DDR3-800.	100 MHz	10.00 NS.	400 MHz	800 million	PC3-6400	6400 MB / s
DDR3-1066.	133 MHz	7.50 ns.	533 MHz	1066 million	PC3-8500.	8533 MB / s
DDR3-1333	166 MHz	6.00 NS.	667 MHz	1333 million	PC3-10600.	10667 MB / s
DDR3-1600.	200 MHz	5.00 NS.	800 MHz	1600 million	PC3-12800.	12800 MB / s
DDR3-1800	225 MHz	4.44 NS.	900 MHz	1800 million	PC3-14400.	14400 MB / s
DDR3-2000	250 MHz	4.00 NS.	1000 MHz	2000 million	PC3-16000	16000 MB / s
DDR3-2133	266 MHz	3.75 ns.	1066 MHz	2133 million	PC3-17000	17066 MB / s
DDR3-2400.	300 MHz	3.33 ns	1200 MHz	2400 million	PC3-19200.	19200 MB / s

The tables indicate exactly peak values, in practice they may be unattainable.

Manufacturer and his Part Number

Each manufacturer to each of its product or part gives its internal production marking, called P / N (Part Number) - part number.

For memory modules from different manufacturers, it looks like this:

Kingston KVR800D2N6 / 1G
Ocz Ocz2M8001G.
Corsair XMS2 CM2X1024-6400C5.

On the site of many memory manufacturers, you can explore how to read them by Part Number.
Modules Kingstonvalueram family:

Kingston Modules Hyperx Family (with additional passive cooling for overclocking):

OCZ labeling can be understood that this is a 1 GB DDR2 module, a frequency of 800 MHz.

On labeling CM2X1024-6400C5. It is clear that this is the DDR2 module of 1024 MB of the PC2-6400 standard and the delays CL \u003d 5.

Some manufacturers instead of the frequency or standard of memory indicate the time in the NA access to the memory chip. At this time, you can understand which frequency is used.
So flows Micron: MT47H128M16HG-3.. The figure in the end indicates that access time is 3 ns (0.003 ms).

According to a well-known forum T \u003d 1 / F, the frequency of the chip f \u003d 1 / T: 1 / 0.003 \u003d 333 MHz.
The frequency of data transmission is 2 times higher - 667 MHz.
Accordingly, this module DDR2-667.

Timing

Timings are delays when accessing memory chips. Naturally, what they are less - the faster the module works.

The fact is that the memory microcircuits on the module have a matrix structure - are presented as a matrix cells with a number of the line and the number of the column.
When referring to the memory cell, the entire string is read in which the desired cell is located.

First select the desired row, then the desired column. At the intersection of the string and number of the column and the desired cell is located. Given the huge volume of modern RAM, such memory matrices are not entirely - for more quick access They are divided into pages and banks.
First, access to the memory can occurs, activate the page in it, then the operation is already working within the current page: the selection of the line and column.
All these actions occurs with a definitely delay of each other.

The main RAM timings are the delay between the feed number and the column number, called the total access time ( RAS TO CAS DELAY, RCD), delay between feeding the column number and receiving the contents of the cell, called the working cycle time ( Cas Latency, Cl), delay between reading the last cell and feeding the number of the new string ( Ras Precharge, RP). Timings are measured in nanoseconds (NA).

These timings are followed by each other in the order of operations and are also indicated schematically. 5-5-5-15 . In this case, all three timing of 5 ns, and the total working cycle is 15 ns since the row is activated.

The main timing is considered Cas Latency.which is often designated abbreviated CL \u003d 5.. It is he who best "slows down" memory.

Based on this information, you can correctly choose the appropriate memory module.

History random access memory, or Oz, started in a distance of 1834, when Charles Bebbage developed an "analytical machine" - in fact, the prototype of the computer. Part of this car, which was responsible for storing intermediate data, he called the "warehouse". Memorizing the information there was organized even purely mechanically, by means of shafts and gears.

In the first generations of computer, electron-ray tubes, magnetic drums were used as RAM, and later magnetic cores appeared, and after them, in the third generation, the computer appeared in chips.

Now RAM is performed by technology Dram. in form factors DIMM and SO-DIMMThis is a dynamic memory organized in the form of integrated semiconductors. It is energy-dependent, that is, the data disappear in the absence of nutrition.

The choice of RAM is not a challenging task today, the main thing here is to understand the types of memory, its purpose and the main characteristics.

Types of memory

SO-DIMM.

SO-DIMM form factor memory is designed for use in laptops, compact ITX-systems, monoblocks - in a word where the minimum physical size of memory modules is important. It differs from the DIMM form factor reduced by about 2 times the module long, and a smaller number of contacts on the board (204 and 360 contacts at SO-DIMM DDR3 and DDR4 against 240 and 288 on the board of the same types of DIMM memory).
For other characteristics - frequency, timings, volume, SO-DIMM modules can be any, and anything fundamental from DIMM does not differ.

Dimm.

DIMM - RAM for full-size computers.
The type of memory you choose should first be compatible with the connector on the motherboard. RAM for computer is divided into 4 types - DDR., DDR2., DDR3 and DDR4..

The memory of the DDR type appeared in 2001, and had 184 contacts. The supply voltage ranged from 2.2 to 2.4 V. The frequency of operation - 400 MHz. It is still found on sale, however, the choice is small. To date, the format is outdated, it will come true only if you do not want to update the system completely, and in the old motherboard connectors only under DDR.

The DDR2 standard has already been released in 2003, received 240 contacts that increased the number of threads, decently accelerating the data transmission bus to the processor. The frequency of DDR2 could be up to 800 MHz (in some cases up to 1066 MHz), and the supply voltage from 1.8 to 2.1 V is slightly less than that of DDR. Therefore, power consumption and heat dissipation decreased.
DDR2 differences from DDR:

· 240 contacts against 120
· New slot incompatible with DDR
· Less power consumption
· Improved design, better cooling
· Above the maximum operating frequency

Also, like DDR, an outdated type of memory - now it will suit that for old motherboards, in other cases it makes no sense, since the new DDR3 and DDR4 faster.

In 2007, RAM was updated with DDR3 type, which is still massively distributed. All the same 240 contacts remained, but the connection slot for DDR3 has become different - no compatibility with DDR2. The frequency of the modules on average from 1333 to 1866 MHz. There are also modules with frequency up to 2800 MHz.
DDR3 is different from DDR2:

· DDR2 and DDR3 slots are incompatible.
· Clock frequency DDR3 works above 2 times - 1600 MHz against 800 MHz at DDR2.
· Differs in reduced supply voltage - about 1.5V, and less power consumption (in versionDDR3L This value is on average even lower, about 1.35 V).
· Delays (timings) DDR3 more than DDR2, but the operating frequency is higher. In general, the speed of DDR3 is 20-30% higher.

DDR3 - Today is a good choice. In many motherboards, on sale connections for memory DDR3, and due to the mass popularity of this type, it is unlikely that it will soon disappear. He is also a bit cheaper DDR4.

DDR4 is a new type of RAM, developed only in 2012. It is an evolutionary development of previous types. The bandwidth of memory rose again, now reaching 25.6 GB / s. The frequency of work also rose - on average from 2133 MHz to 3600 MHz. If you compare a new type with DDR3, which lasted on the market for the whole 8 years and got a mass distribution, then the productivity increase is insignificant, moreover, not all motherboards and processors support a new type.
Differences DDR4:

· Incompatibility with previous types
· Reduced supply voltage - from 1.2 to 1.05 V, power consumption also decreased
· Working frequency of memory up to 3200 MHz (can reach 4166 MHz in some placters), while, of course, grew proportionally timing
· Can slightly exceed the speed of DDR3

If you already have a DDR3 strip, then there is no point in changing them on DDR4. When this format is distributed massively, and all motherboards will already support DDR4, the transition to a new type will occur with the update of the entire system. Thus, it is possible to summarize that DDR4 is rather marketing than a real new type of RAM.

What frequency of memory to choose?

The frequency selection must be started with checking the most supported frequencies by your processor and motherboard. The frequency is higher than the supported processor makes sense to take only when the processor is accelerated.

To date, you should not choose a memory with a frequency below 1600 MHz. An option 1333 MHz is permissible in the case of DDR3, if this is not the ancient modules that are not swollen from the seller, which will clearly be slower than new ones.

The optimal version for today is the memory with a frequency interval from 1600 to 2400 MHz. The frequency above almost does not have the advantages, but it is much more expensive, and as a rule is overclocked modules with raised timings. For example, the difference between modules at 1600 and 2133 MHz in a number of work programs will be no more than 5-8%, in the game the difference may be even less. Frequencies in 2133-2400 MHz should be taken if you are engaged in video / audio encoding, rendering.

The difference between frequencies of 2400 and 3600 MHz will cost you quite expensive, while not adding a speedy speed.

What is the volume of RAM to take?

The amount that you need depends on the type of work done on the computer, from the installed operating system, from the programs used. It is also not worth overlooking the most supported amount of memory by your motherboard.

Volume 2 GB - Today, it may not be enough for only to view the Internet. More than half will eat the operating system remaining enough for a leisurely work of undemanding programs.

Volume 4 GB - It is suitable for a computer of the middle hand, for a home-made PC media center. Enough to watch movies, and even play undemanding games. Modern - alas, with difficulty pulls. (Will be the best choiceIf you have a 32-bit operating room windows systemwhich sees no more than 3 GB of RAM)

Volume 8 GB (or 2x4gb set) - Recommended volume for today for a full-fledged PC. This is enough for almost any games, to work with any demanding resource software. The best choice for a universal computer.

The volume of 16 GB (or 2x8GB sets, 4x4GB) will be justified if you work with graphics, heavy programming environments, or constantly render video. It is also perfect for maintaining online streams - here with 8 GB can be rolling, especially with high quality video broadcast. Some games B. high permissions And with HD textures, it can be better to conduct themselves from 16 GB of RAM on board.

Volume 32 GB (Set 2x16GB, or 4x8GB) - While a very controversial choice is useful for some very extreme work tasks. It will be better to spend money on other components of the computer, it will be more affected by its speed.

Work modes: Better 1 memory bar or 2?

RAM can work in single-channel, two-, three- and four-channel modes. Definitely, if there is a sufficient number of slots on your motherboard, it is better to take a somewhat smaller volume instead of one memory strip. Access speed to them will grow from 2 to 4 times.

To work in two-channel mode, you need to install the planks in the slots of the same color on the motherboard. As a rule, the color is repeated through the connector. It is important that the memory frequency in two straps is the same.

- Single Chanell Mode. - single-channel mode of operation. It turns on when one memory bar is installed, or different modules operating at different frequency. As a result, the memory operates at the frequency of the slowest plank.
- Dual Mode. - two-channel mode. It works only with the memory modules of the same frequency, increases the speed of operation by 2 times. Manufacturers produce specifically for this memory modules sets in which there may be 2 or 4 identical planks.
- Triple Mode. - Works on the same principle as the two-channel. In practice, it is not always faster.
- Quad mode. - Four-channel mode, which works on the principle of two-channel, by respectively increasing the speed of operation 4 times. Used, where you need exclusively high speed - for example, in servers.

- Flex Mode.- A more flexible version of the two-channel mode of operation, when the planks of different volume, and the same only frequency. At the same time, the same module volumes will be used in two-channel mode, and the remaining volume will function in one-channel.

Do you need a radiator?

Now there are no time for a long time when at a voltage of 2 V, the frequency of work in 1600 MHz was achieved, and as a result, a lot of heat was released, which it was necessary to somehow get out. Then the radiator could be the criterion of the survival of the overclocked module.

Currently, the memory energy consumption has been very decreased, and the radiator on the module can be justified from a technical point of view, only if you are enjoying overclocking, and the module will work on your frequencies for it. In all other cases, radiators can be justified, except that, beautiful design.

In case the radiator is massive, and significantly increases the height of the memory plank - this is a significant minus, because it may prevent you from putting a processor supercouper into the system. There are, by the way, special low-profile memory modules intended for installation in compact enclosures. They are somewhat more expensive than the modules of the usual size.

What are timings?

Timing, or latency (Latency) - one of the most important characteristics RAM, determining its speed. Find the general meaning of this parameter.

Simplified RAM can be represented as a two-dimensional table in which each cell carries information. Access to cells occurs at the specifying the number of the column and string, and the indication does this happen using a strobe pulse access to the string Ras.(ROW ACCESS STROBE.) and the strobe pulse access to the column Cas. (Acess Strobe) By changing the voltage. Thus, for each tact of work occur Ras. and Cas., and between these appeals and recording / reading commands, there are certain delays that are called timings.

In the description of the RAM module, you can see five timings that are written to the sequence of digits through a hyphen, for example, 8-9-9-20-27 .

· TRCD (Time of Ras to Cas Delay)- Timing, which determines the delay from the RAS pulse to Cas
· Cl (Time of Cas Latency) - Timeing determining the delay between the recording / reading command and the CAS pulse
· TRP (TIME OF ROW PRECHARGE) - Timeing defining the delay when transitions from one line to the next
· tRAS (Time of Active to Precharge Delay) - Timing, which determines the delay between the activation of the line and the end of working with it; It is considered the basic meaning
· Command Rate.- determines the delay between the selection command selection command on the module to the activation of the string; This timing is not always indicated.

If it is even easier to talk, then it is important for the timings to know only one thing - than their values \u200b\u200bare less, the better. At the same time, the planks may have the same frequency of work, but different timings, and the module with smaller values \u200b\u200bwill always be faster. So it is worth choosing minimal timings, for DDR4, the target of the average values \u200b\u200bwill be timings 15-15-15-36, for DDR3 - 10-10-10-30. It is also worth remembering that the timings are associated with the frequency of memory, so that during the acceleration most likely you will have to raise the timings, and vice versa - you can manually lower the frequency, reducing the timings. It is most profitable to pay attention to the combination of these parameters, choosing the balance rather, and do not chase at extreme values \u200b\u200bof the parameters.

How to decide on the budget?

Having a greater amount, you can afford a larger amount of RAM. The main difference of cheap and expensive modules will be in timings, frequency of work, and in brand - known, advertised can cost a bit more expensive than noname modules of incomprehensible manufacturer.
In addition, additional money is the radiator installed on the modules. Not all of the planks are needed, but the manufacturers are now not stored on them.

The price will also depend on timings than they are lower than the speed, and, accordingly, the price.

So, having up to 2000 rubles, You can purchase a 4 GB memory module, or 2 modules of 2 GB, which is preferable. Choose depending on what allows your PC configuration. DDR3 type modules will be almost twerded than DDR4. With such a budget, it is wiser to take exactly DDR3.

Group up to 4000 rubles Includes modules with a volume of 8 GB, as well as 2x4 GB kits. This is the optimal choice for any tasks, except for professional work with video, and in any other heavy environments.

In sum up to 8,000 rubles The amount of memory in 16 GB will cost. Recommended for professional purposes, or for avid gamers - even about the reserve, waiting for new demanding games.

If not a problem to spend up to 13,000 rubles, the best choice will be inserted into a set of 4 planks of 4 GB. For this money, you can choose even radiators preferably, possibly for subsequent acceleration.

More than 16 GB without work in professional hard environments (and not in all) I do not advise you, but if I really want, then for the amount from 13,000 rubles You can climb into Olympus, purchasing a set of 32 GB or even 64 GB. True, it will not be much sense for an ordinary user or gamer in this - it is better to spend money, say, on the flagship video card.

Description

In addition to separation of bandwidth and capacity, modules are divided by:

the presence of an additional memory chip for error correction code. Denote by ECC characters, for example, as follows: PC2-6400 ECC;
the presence of a specialized addressing microcircuit is REGISTER.
"Normal" modules are indicated as "non-registered" or "unbuffered". Register in buffered - "registered" - modules improves the quality of the command-address lines signal (at the price of an additional tact of delay when contacting), which allows you to raise frequencies and use up to 36 memory chips to the module, creating an increased tank modules that are usually used in servers and workers Stations. Almost all Modules that have been released now are also equipped with ECC.
aMB microcircuit (Advanced Memory Buffer). Such modules are called completely buffered (Fully buffered) are denoted by letters F or FB and have another key location on the module. This further development of the idea of \u200b\u200bregistered modules - Advanced Memory Buffer exercises unnecessary address signals, but also data, and uses the serial bus to the memory controller instead of parallel. These modules cannot be installed in motherboards developed for other types of memory, and the key position is hampered.

As a rule, even if the motherboard supports REGISTERED and UNBUFFERED (normal memory) modules, modules different types (REGISTERED and UNBUFFERED) can not work in conjunction on one channel. Despite the mechanical compatibility of the connector, the registered memory will simply not start in the motherboard designed to apply conventional (non-buffered) memory and vice versa. The presence / absence of ECC in no way affects the situation. All this concerns both the usual DDR and DDR-II.

It is categorically impossible to use registered memory instead of ordinary memory and vice versa. No exceptions. The only exception is currently two-processor LGA1366 boards that work both with normal and registered DDR-III, but it is impossible to mix two types of memory in one system.

Advantages Compared to DDR

Higher bandwidth
As a rule, less power consumption
Improved construction constructing

Disadvantages compared to DDR

Usually higher CAS-latency (from 3 to 6)
The final delays in the same (or even higher) frequencies turn out to be higher

DDR2 gradually displaces DDR3.

Literature

V. Solomenchuk, P. Solomenchuk Iron PC. - 2008. - ISBN 978-5-94157-711-8

Notes

Links

Types of dynamic memory with arbitrary access (DRAM)
Asynchronous	FPM RAM. · EDO RAM.
Synchronous	SDRAM · DDR SDRAM · Mobile DDR (LPDDR) · DDR2 SDRAM · DDR3 SDRAM · DDR4 SDRAM.
Graphic	Vram. · Wram. · Mdram. · SGRAM · Gddr. · GDDR2. · GDDR3 · GDDR4. · GDDR5
Rambus.	Rdram. · XDR Dram. · XDR2 Dram.