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What is ddr2 in a computer. Timings and frequency of RAM

The component market is constantly replenished with new developments and innovations with enviable regularity, which is why many users, whose funds clearly do not allow them to acquire new hardware in time, have doubts about the power and performance of their computer as a whole. At all times, the discussion of a lot of questions on technical forums about the relevance of their components never subsides. In this case, the questions concern not only the processor, video card, but even the RAM. However, even in spite of the entire dynamics of the development of computer hardware, the relevance of the technologies of previous generations is not lost as quickly. This also applies to components

DDR2 memory: from the first days on the market to the decline of popularity

DDR2 is the second generation with random access (from the English Synchronous Dynamic random access memory - SDRAM), or, in the formulation familiar to any user, the next generation of random access memory after DDR1, which has become widespread in the segment of personal computers.

Developed back in 2003, the new type was able to fully gain a foothold in the market only by the end of 2004 - only at that time chipsets with DDR2 support appeared. Actively touted by marketers, the second generation was presented as nearly twice the powerful alternative.

What is worth highlighting from the differences is the ability to operate at a significantly higher frequency, transmitting data twice in one clock cycle. On the other hand, the standard negative aspect of raising frequencies is the increase in latency during operation.

Finally, by the mid-2000s, the new type fundamentally infringed the position of the previous, first, and only by 2010 DDR2 was significantly squeezed out by the new DDR3 that replaced it.

Features of the device

The distributed DDR2 RAM modules (commonly referred to as "dies") had some distinctive features and varieties. And although the new for its time did not frankly amaze with an abundance of variations, however, even external differences immediately caught the eye of any buyer at first sight:

Single-sided / double-sided SDRAM plate, on which the microcircuits are located on one or both sides, respectively.
DIMM is the standard form factor for SDRAM today (synchronous dynamic random access memory, which is DDR2). Mass use in general purpose computers began in the late 90s, which was mainly facilitated by the appearance of the Pentium II processor.
SO-DIMM is a shortened form factor of SDRAM module specially designed for laptop computers... Notebook SO-DIMM DDR2 dies had several significant differences from standard DIMMs. This is a module with smaller physical dimensions, lower power consumption and, as a result, lower performance level compared to the standard DIMM factor. An example of a DDR2 RAM module for a laptop can be seen in the photo below.

In addition to all the above features, one should also note the rather mediocre "shell" of the dies of those times - almost all of them, with rare exceptions, were then represented only by standard boards with microcircuits. Marketing in the segment of computer hardware was only just beginning to spin up, so there were simply no samples on sale with radiators of various sizes and designs that are familiar to modern RAM modules. Until now, they perform primarily a decorative function, rather than the task of removing the generated heat (which, in principle, is not characteristic of DDR-type RAM).

In the photo below, you can see how the DDR2-667 RAM modules look with a heatsink.

Compatibility key

DDR2 memory in its design has an extremely important difference from the previous DDR - lack of backward compatibility. In the samples of the second generation, the slot in the contact area of \u200b\u200bthe strap with the RAM slot on the motherboard was already located differently, which is why it is physically impossible to insert a DDR2 die into a DDR slot without breaking one of the components.

Volume parameter

For serial motherboards (any motherboard for home / office use), the DDR2 standard could offer a maximum volume of 16 gigabytes. For server solutions, the volume limit reached 32 gigabytes.

It is also worth paying attention to one more technical nuance: the minimum volume of one die is 1 GB. In addition, there are two more variants of DDR2 modules on the market: 2Gb and 8Gb. Thus, in order to get the maximum possible supply of RAM of this standard, the user will have to install two bars of 8 GB each or four of 4 GB, respectively.

Data transmission frequency

This parameter is responsible for the ability of the memory bus to pass as much information as possible per unit of time. A higher frequency means more data can be transferred, and here DDR2 memory significantly outperformed the previous generation, which could work in the range from 200 to 533 MHz maximum. After all, the minimum frequency of the DDR2 bar is 533 MHz, and the top-end units, in turn, could boast of overclocking to 1200 MHz.

However, with the increase in the memory frequency, the timings naturally increased, on which the memory performance depends not least.

About timings

Timing is the time interval from the moment data is requested until it is read from RAM. And the more the frequency of the module increased, the longer it took for the RAM to complete operations (not until colossal delays, of course).

The parameter is measured in nanoseconds. The most affecting performance is the latency timing (CAS latency), which is denoted as CL * in the specifications (any number can be specified instead of *, and the smaller it is, the more operative the memory bus will work). In some cases, strap timings are indicated by a three-character combination (for example, 5-5-5), but the most critical parameter will be just the first number - it always indicates memory latency. If the timings are indicated in a four-digit combination, in which the last value is strikingly larger than all the others (for example, 5-5-5-15), then this is the duration of the total working cycle in nanoseconds.

An old man who does not lose shape

With its appearance, the second generation caused a lot of noise in the computer circles, which provided it with considerable popularity and excellent sales. DDR2, like its predecessor generation, could transfer data on both cuts, however, a faster bus with the ability to transfer data significantly increased its performance. In addition, a higher energy efficiency was also a positive point - at the level of 1.8 V. And if this hardly had any effect on the overall picture of the computer's power consumption, then it had a purely positive effect on the service life (especially with intensive work of iron).

However, technologies ceased to be such, if not for further development. This is exactly what happened with the appearance of the next generation DDR3 in 2007, whose task was to gradually but surely oust the outdated DDR2 from the market. However, does this "obsolescence" really mean complete non-competitiveness with new technology?

One on one with the third generation

Besides the traditional backward incompatibility, DDR3 introduced a number of several technical innovations to RAM standards:

The maximum supported volume for serial motherboards has increased from 16 to 32 GB (while the figure for one module could reach 16 GB instead of the previous 8).
Higher data transmission frequencies, the minimum of which is 2133 MHz, and the maximum is 2800 MHz.
Finally, the standard for each new generation reduced power consumption: 1.5 V versus 1.8 V for the second generation. In addition, two more modifications were developed based on DDR3: DDR3L and LPDDR3, consuming 1.35 V and 1.2 V, respectively.

Along with the new architecture, timings have also increased, but the drop in performance from this is offset by higher operating frequencies.

How the buyer decides

The buyer is not a development engineer; in addition to technical characteristics, the price of the product itself will be no less important to the buyer.

At the start of sales of a new generation of any computer hardware, its cost will usually be higher. The same new type of random access memory first comes to the market with a very large price difference compared to the previous one.

However, the gain in performance between generations in most applications, if not absent at all, is simply ridiculous indicators, clearly not worthy of large overpayments. The only right moment to switch to a new generation of RAM is the maximum drop in its price tag to the level of the previous one (this always happens in the SDRAM sales segment, the same was the case with DDR2 and DDR3, the same happened now with DDR3 and the new DDR4). And only when the price of the overpayment between the last and the previous generation is the very minimum (which is adequate for a small increase in performance), then only in this situation can you think about replacing the RAM.

In turn, owners of computers with DDR2 memory are most rational to acquire a new type of RAM only with a thorough upgrade with a corresponding support for this newest type, and a new motherboard (and even today it makes sense to upgrade to the level of components supporting DDR4 memory: its current price is on a par with DDR3, and the increase between the fourth and second generations will be much more noticeable than between the third and second).

Otherwise, if such an upgrade is not planned by the user at all, then it is quite possible to get by with the same DDR2, the price of which is now relatively low. It will be enough just to increase, if necessary, the total amount of RAM with similar modules. Allowable memory limits of this type, even today, more than cover all the needs of most users (in most cases, installing additional module DDR2 2Gb), and the performance lag with the next generations is completely uncritical.

The minimum prices for RAM modules (only samples of proven brands Hynix, Kingston and Samsung are taken into account) may vary depending on the region of residence of the buyer and the store he has chosen.

Date of publication:

25.06.2009

As you know, RAM is a major contributor to computer performance. And it is clear that users are trying to increase the amount of RAM to the maximum.
If 2-3 years ago there were literally several types of memory modules on the market, now there are much more of them. And it became more difficult to understand them.

In this article, we will look at various designations in the labeling of memory modules to make it easier for you to navigate them.

First, let's introduce a number of terms that we need to understand the article:

strip ("die") - a memory module, a printed circuit board with onboard memory chips installed in a memory slot;
one-sided bracket - a memory strip with memory chips located on one side of the module.
double-sided bracket - a memory strip with memory chips located on both sides of the module.
RAM (Random Access Memory, RAM) - random access memory, in other words, random access memory. This is a volatile memory, the contents of which are lost in the absence of power.
SDRAM (Synchronous Dynamic RAM) - synchronous dynamic random access memory: all modern memory modules have just such a device, that is, they require constant synchronization and updating of content.

Consider the markings

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 line is the amount of memory modules. In particular, in the first case it is 4 GB, and in the second it is 1 GB. True, 4 GB in this case are implemented not by one memory stick, but by two. This is the so-called Kit of 2 - a set of two strips. Typically, such kits are purchased to install brackets in dual channel mode in parallel slots. The fact that they have the same parameters will improve their compatibility, which is beneficial for stability.

Type of shell

DIMM / SO-DIMM is a type of memory strip enclosure. All modern memory modules are available in one of the two specified designs.
DIMM (Dual In-line Memory Module) - a module with contacts located in a row on both sides of the module.
DDR SDRAM is available in 184-pin DIMMs, while DDR2 SDRAM is available in 240-pin strips.

Laptops use smaller memory modules called SO-DIMM (Small Outline DIMM).

Memory type

Memory type is the architecture by which the memory chips themselves are organized. It affects everything specifications memory - performance, frequency, supply voltage, etc.

At the moment, 3 types of memory are used: DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM. Of these, DDR3 is the most efficient, the least energy consuming.

Data rates for memory types:

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

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

All types of memory modules differ in supply voltage and connectors and do not allow being inserted into each other.

The data transfer frequency characterizes the potential of the memory bus for data transfer per unit of time: the higher the frequency, the more data can be transferred.

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

For a comprehensive assessment of the capabilities of RAM, the term memory bandwidth is used. It takes into account the frequency at which data is transmitted and the width of the bus and the number of memory channels.

Bandwidth (B) \u003d Frequency (f) x memory bus width (c) x number of channels (k)

For example, when using dDR memory400 400 MHz and dual channel memory controller bandwidth will be:
(400 MHz x 64 bit x 2) / 8 bit \u003d 6400 MB / s

We divided by 8 to convert Mbps to Mbps (in 1 byte 8 bits).

Memory module speed standard

To make it easier to understand the speed of the module, the designation also indicates the memory bandwidth standard. It just shows what bandwidth the module has.

All of these standards begin with the letters PC and are followed by numbers indicating the memory bandwidth in MB per second.

Module name	Bus 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	Bus frequency	Data transfers per second	Name of the standard	Peak data 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

Peak values \u200b\u200bare indicated in the tables; in practice they may not be achievable.

Manufacturer and its part number

Each manufacturer gives each of his products or parts its internal production marking, called P / N (part number) - part number.

For memory modules different manufacturers it looks something like this:

Kingston KVR800D2N6 / 1G
OCZ OCZ2M8001G
Corsair XMS2 CM2X1024-6400C5

On the site of many memory manufacturers, you can study how their Part Number is read.
Modules Kingstonof the ValueRAM families:

Kingston modules of the HyperX family (with additional passive cooling for overclocking):

From the OCZ marking, you can understand that this is a 1 GB DDR2 module with a frequency of 800 MHz.

By marking CM2X1024-6400C5 it is clear that this is a 1024 MB DDR2 module of the PC2-6400 standard and CL \u003d 5 delays.

Some manufacturers indicate the time in ns of access to the memory chip instead of the frequency or memory standard. By this time, you can understand which frequency is used.
This is what the Micron does: MT47H128M16HG-3... The number at the end indicates that the access time is 3 ns (0.003 ms).

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

Timings

Timings are delays when accessing memory chips. Naturally, the smaller they are, the faster the module works.

The fact is that the memory chips on the module have a matrix structure - they are presented in the form of matrix cells with a row number and a column number.
When accessing a memory cell, the entire row is read in which the required cell is located.

First, the desired row is selected, then the desired column. At the intersection of the row and the column number, the desired cell is located. Taking into account the huge amount of modern RAM, such memory matrices are not whole - for more quick access to memory cells, they are divided into pages and banks.
First, the memory bank is accessed, the page is activated in it, then work is already taking place within the current page: row and column selection.
All these actions take place with a definite delay in relation to each other.

Basic RAM timings are the delay between feeding the row number and the column number, called time full access (RAS to CAS delay, RCD), the delay between feeding the column number and receiving the cell contents, called the cycle time ( CAS latency, CL), the delay between reading the last cell and feeding a new line number ( RAS precharge, RP). Timings are measured in nanoseconds (ns).

These timings go one after another in the order of operations and are also indicated schematically 5-5-5-15 ... In this case, all three timings are 5 ns each, and the total duty cycle is 15 ns from the moment the line is activated.

The main timing is considered CAS latency, which is often abbreviated CL \u003d 5... It is he who "inhibits" memory to the greatest extent.

Based on this information, you will be able to choose the right memory module wisely.

The article is constantly updated. Last update 04.01.2013 p.
RAM (RAM) - this is special memory (random access memory), which temporarily stores data and instructions necessary for the processor to perform operations, and the access time to this memory (for the processor) does not exceed one cycle.
Data transfer to / from RAM is performed directly through the processor's ultra-fast cache memory (L2 or L3).

Timing (latency) of RAM is the time delay of the data exchange signal, i.e. this is the short time delay for memory "responsiveness" to data I / O. The memory performance directly depends on the timings and, as a result, the performance of the entire system is very dependent.
Timings are indicated on the memory modules as: 4-4-4-12, 6-6-6-18, 9-9-9-27 or as part of the CL4, CL5, CL9 memory module marking.

The first step in choosing RAM is your choice of motherboard and processor.
Since the memory is directly installed in the motherboard and the type of memory will depend on the mat. boards.
We wrote about this:

And the processor will work directly with the installed RAM, and the new processors have a built-in controller for exchanging data with the RAM.
About this here:

Memory type.

The following types of memory are used in desktop computer systems:

DDR (double data rate - double speed data transfer) - currently this type of memory is outdated and almost never used. The module has 184 contacts. Standard supply voltage 2.5 V.
Marked as PC-2700 333 Mhz, PC-3200 400 Mhz.

Since this type of memory has long been discontinued, we will not focus on it.

DDR2 is a currently widespread type of memory. DDR2, unlike DDR, allows you to sample 4 data bits per clock at once (4n-prefetch), DDR only 2 bits per clock (2n-prefetch), i.e. DDR2 is capable of transferring 4 bits of information from the cells of the memory chip to the input-output buffers per memory bus cycle. The module is designed as a printed circuit board with 240 contacts (120 on each side) and has a standard supply voltage of 1.8 V.
Marked as PC-5300 667 Mhz, PC-6400 800 Mhz, PC-8500 1066 Mhz.

This type of memory is now widely used in desktop office and gaming computers. Due to the high frequency, low timings (latencies) and double the sampling rate, the memory shows high performance results.

DDR3 - A new and no less common type of memory. DDR3 - allows you to sample 8 bits of data per clock (8n-prefetch). The module, just like DDR2, is made in the form of a 240-pin board (only the key / slot is displaced and you cannot install DDR3 in the DDR2 slot), and the standard supply voltage is only 1.5 V.
Labeled PC-10600 1333 Mhz, PC-12800 1600 Mhz, PC-14400 1800 Mhz, PC-15000 1866 Mhz, PC-16000 2000 Mhz.

At the moment, this type of memory displaces DDR2 from new systems and will completely replace it in the future. DDR3 found application only in gaming and overclocking systems, but is also fully implemented in multimedia systems and laptops. Since it has higher operating frequencies and much higher bandwidth in comparison with DDR2.
The power consumption of DDR3 memory is approximately 40% less than that of DDR2 memory, which is very important for notebooks and mobile systems.

DDR2 memory is no longer cost effective for new systems. Is that for office computers based on an earlier one with an integrated graphics core.

And when purchasing new components for home and gaming-overclocking systems, at the moment, you need to focus on DDR3. Since, all new mat. boards and new processors only support DDR3.
The only thing to consider is that DDR3 has slightly higher timings compared to DDR2, but due to its higher frequency and lower power consumption, it is the best choice for desktop and mobile systems.

Memory frequency.

The arithmetic here is simple: the higher the frequency, the more efficient the memory.
The main thing is that your motherboard supports the memory frequency you have chosen.

But do not forget that as the frequency increases, the timings (delays) also increase.

The golden mean in DDR3 is 1600 Mhz with CL7 or CL8 timings.
For DDR2, the optimal frequency is 1066 Mhz with CL5 timings.

Timings.

Timings (latency) are in other words memory latency. That is, the speed of memory "responsiveness" is determined by timings.
It turns out that the lower the timings, the faster the memory.

DDR had standard CL3 timings (3-3-3-9) at 400 MHz
DDR2 standard CL6 timings (6-6-6-18) at 800 Mhz
DDR3 has CL9 (9-9-9-27) timings at 1600 Mhz

But there are modules with reduced timings / increased performance. Such modules are a little more expensive than standard ones, but they can significantly speed up the system.
They are sometimes called overclocking memory.
You can buy memory, the timings of which, for example, at the same frequency for DDR2 800 Mhz are only CL4 (4-4-4-12), and for DDR3 1600 Mhz - CL7 (7-7-7-21).
The only thing is that to ensure such a mode of operation, some manufacturers indicate the supply voltage of their chips above the nominal.

Dual-Triple-Channel memory and KIT memory.

The two-channel mode began to be used relatively recently. And the three-channel one is based on the X58 gaming chipset of the LGA 1366 platform for the Core i7.

Dual-channel mode is a mode of operation of RAM, in which memory modules work in pairs, that is, the 1st with the 3rd, and the 2nd with the 4th (in the three-channel - "triplets" 1-3-5, 2-4 -6), and each pair is on its own channel - while in single-channel mode all memory modules are served simultaneously by one controller (so to speak, they work in one channel).
The total amount of available memory in three- or two-channel mode (as well as in single-channel mode) is equal to the sum of all the volumes of the installed memory modules.

The two-channel robots memory mode gives a very good performance boost. In theory, this mode doubles the memory bandwidth. But in practice, the increase in dual-channel versus single-channel is from 10% to 70% (depending on the application).
Well, the gain of the three-channel is still insignificant, in comparison with the two-channel, only a couple of percent.

The memory of one volume, one frequency, one manufacturer, one type will work in three-two-channel mode. And it is also necessary that the motherboard and processor support this mode of operation. You can read about this in the articles:

But sometimes there are exceptions.
Two (three) completely identical memory modules (frequency, timings, size, manufacturer, type, and even from the same batch) may "refuse" to work in Dual Channel (Triple Channel) and lead the system to a blue screen.
It's like a lottery who is lucky enough to launch two or three regular modules, and who is not.
And you cannot make any claims under the guarantee, since they work perfectly individually and in single-channel mode.

For ease of launching the memory into DualChannel mode, motherboard manufacturers "paint" the memory slots of one channel with one color, the other with another. Accordingly, to make the memory work in dual-channel mode, you need to install modules in slots of the same color (more precisely, read the instructions of the motherboard).
(the exception is when there are only two slots on the board, then you can check the number of channels with the CPU-Z program)

Single-channel memory operation mode is when memory is inserted into adjacent slots (of different colors):

Dual-channel mode, memory is installed in pairs 1-3, 2-4 (in slots of the same color):

IMPORTANT!!! If you, on the motherboard, support dual-channel memory robots, and the memory is inserted into the 1st and 3rd slots (for example, 2 pcs. 1Gb each) and you decide to deliver the third bar to the 2nd or 4th slot ( let's say the same 1Gb bar). Then you will "lose" the dual-channel memory mode, and the controller will go into single-channel.
The increase from the added memory will not be high, and from the loss of the dual-channel mode, the performance will drop somewhat.
Add memory in pairs to save dual channel mode !!!

Three-channel mode, memory is installed in "triplets" 1-3-5, 2-4-6 (also in slots of the same color):

There are special sets of memory modules for work in multichannel modes.
So-called Kit memory (Kit-set) - this kit includes two (three) modules, of the same manufacturer, with the same frequency, timings and memory type.
But the most important thing is that such modules are carefully selected and tested, by the manufacturer itself, for operation in pairs (triplets) in two- (three-) channel modes and do not imply any surprises in operation and configuration.

Appearance of KIT-kits:
for two-channel mode

for three-channel

In addition, such memory modules are equipped with passive cooling heatsinks, the presence of which allows the chips to cool themselves.
This is an indisputable plus and has a positive effect on the stability of the memory.

Based on performance gain tests, the optimal choice for all systems (including office ones) is the Dual Channel memory mode.

Dual channel performance tests:.

That is, for example, it is better to take 2 strips with a volume of 2 Gb each, and put them in two-channel mode than with one 4 Gb strip.
Or 2 pieces of 1 Gb each, than one with a volume of 2 Gb.
The amount of memory is the same, but the performance gain is 10-70% more, depending on the application.

The only thing is that to provide a two-channel mode in an office computer, simple identical modules (preferably from one batch) are enough, then for home gaming, multimedia, gaming-overclocking systems, we strongly recommend purchasing KIT-memory (KIT-set).

The required amount of memory.

Today the minimum required amount of RAM is 2 Gb. ...
This is enough for any office system.

But the best choice is 4 Gb (2x2Gb). This is enough for any gaming machine.
Installation of 4 pieces is not desirable. 1 Gb each, this will lead to more power consumption and less stability when pairing in multi-channel mode.

Note: for the operating room windows system used all 4 Gb of RAM, you need to install a 64-bit Windows OS. Since a 32-bit system will use 3.12 Gb out of 4 Gb installed.

More RAM will be needed mainly by enthusiasts or professionals to process graphics and design models in high resolutions.

Installation of 8 Gb (2x4 Gb) and higher is justified in systems with SSD, and which uses a hard disk for short-term storage of files processed by RAM.
Disabling the paging file is relevant only on those systems where it is used SSD disk... To extend its service life.

And at the end of the article, I would like to say that there is never a lot of RAM, but there is no need for extra memory.
It is necessary to take exactly as much as necessary, and for the "extra" money, choose Kit-memory with lower timings and with a higher frequency.

RAM is a special microcircuit used to store all kinds of data. There are many types of these devices, they are produced by various companies. The best producers are most often of Japanese origin.

What is it and what is it for?

RAM (the so-called RAM memory) is a type of volatile microcircuit used to store all kinds of information. Most often it contains:

machine code of programs currently executing (or in standby mode);
input and output data.

Photo: RAM from different manufacturers

Data exchange between the central processor and RAM is carried out in two ways:

using ultra-fast ALU register;
across special cache (if available in the design);
directly (directly via the data bus).

The devices under consideration are circuits based on semiconductors. All information stored in all kinds of electronic components, remains available only if there is electric current... As soon as the voltage is turned off completely, or a short-term power cut occurs, then everything that was contained inside the RAM is erased or destroyed. ROM devices are an alternative.

Types and amount of memory

The board today can have a volume of several tens of gigabytes. Modern technical means allow you to use it as quickly as possible. Most operating systems equipped with the ability to interact with such devices. There is a proportional relationship between the amount of RAM and the cost. The larger its size, the more expensive it is. And vice versa.

Also, the considered devices may have different frequencies. This parameter determines how quickly the interaction between RAM and other PC devices (CPU, data bus and video card) is carried out. The higher the operating speed, the more operations the PC will perform per unit of time.

The value of this characteristic also directly affects the cost of the device in question. The modern fastest modification can "memorize" 128 GB. It is produced by a company called Hynix and has the following performance characteristics:

All modern RAM can be divided into two types:

static;
dynamic.

Static type

More expensive today is the static microcircuit. It is labeled as SDRAM. Dynamic is cheaper.

The distinctive features of the SDRAM version are:

Also, a distinctive feature of RAM is the ability to select the bit to which any information will be recorded.

The disadvantages include:

low recording density;
relatively high cost.

All kinds of computer random access memory devices (SDRAM and DRAM) have external differences. They are contained in the length of the contact part. Its shape also differs. The designation of the RAM is located both on the sticker label and printed directly on the strap itself.

There are many different SDRAM modifications available today. It is designated as:

DDR 2;
DDR 3;
DDR 4.

Dynamic type

Another type of microcircuit is designated as DRAM. It is also completely volatile, and the write bits are accessed in an arbitrary manner. This type is widely used in most modern PCs. It is also used in those computer systems where latency requirements are high - DRAM performance is an order of magnitude higher than SDRAM.

DRAM - dynamic memory

Most often, this type has a form factor of the DIMM type. The same design solution is used for the manufacture of the static circuit (SDRAM). A feature of the DIMM design is that there are contacts on both sides of the surface.

OP parameters

The main criteria for choosing microcircuits of this type are their operating parameters.

You should focus primarily on the following points:

frequency of work;
timings;
voltage.

They all depend on the type specific model... For example, the DDR 2 will perform various actions definitely faster than the DDR 1 bar. Since it has more outstanding performance characteristics.

Timing is the time delay of information between different components of the device. There are quite a few types of timings, all of them directly affect performance. Small timings allow you to increase the speed of various operations. There is one unpleasant proportional dependence - the higher the speed of the random access memory, the higher the timings.

The way out of this situation is to increase the operating voltage - the higher it is, the less timings become. The number of operations performed per unit of time increases at the same time.

Frequency and speed

The higher the RAM bandwidth, the higher its speed. Frequency is a parameter that determines the bandwidth of the channels through which various kinds of data are transferred to the CPU through the motherboard.

It is desirable that given characteristic coincided with the permissible speed of the motherboard.

For example, if the bracket supports 1600 MHz, and the motherboard does not exceed 1066 MHz, then the speed of data exchange between the RAM and the CPU will be limited by the capabilities of the motherboard. That is, the speed will be no more than 1066 MHz.

Performance

Performance depends on many factors. The number of planks used has a very large effect on this parameter. Dual-channel RAM works an order of magnitude faster than single-channel RAM. The ability to support multichannel modes is indicated on a sticker located over the board.

These designations are as follows:

To determine which mode is optimal for a particular motherboard, you need to count the total number of slots for connection, and divide them by two. For example, if there are 4 of them, then you need 2 identical strips from the same manufacturer. When installed in parallel, the Dual mode is activated.

Working principle and functions

The operation of the OP is implemented quite simply, data writing or reading is carried out as follows:

Each column is connected to an extremely sensitive amplifier. It registers the flow of electrons that occur when the capacitor is discharged. In this case, the corresponding command is given. Thus, access to the various cells located on the board takes place. There is one important nuancewhich you should definitely know. When an electrical impulse is applied to any line, it opens all of its transistors. They are directly connected to it.

From this we can conclude that one line is the minimum amount of information that can be read when accessing. The main purpose of RAM is to store various kinds of temporary data that are necessary while personal Computer the operating system is on and running. The most important executable files are loaded into RAM, the CPU executes them directly, simply saving the results of the operations performed.

Photo: interaction of memory with the processor

The cells also store:

executable libraries;
key codes, which were pressed;
results of various mathematical operations.

If necessary, everything in RAM is cPU can save to hard drive. And to do it in the form in which it is necessary.

Manufacturers

In stores you can find great amount RAM from a variety of manufacturers. A large number of such products began to be supplied from Chinese companies.

To date, the most productive and high-quality products are the following brands:

Kingston;
Hynix;
Corsair;
Kingmax.
Samsung.

It is a compromise between quality and performance.

RAM characteristics table

The same type of RAM from different manufacturers has similar performance characteristics.

That is why it is correct to compare, taking into account only the type:

Performance and price comparison

The performance of RAM directly depends on its cost. You can find out how much a DDR3 module costs in your nearest computer store, and you should also familiarize yourself with the price of DDR 1. By comparing their operating parameters and price, and then testing, you can easily verify this.

It is most correct to compare RAM of the same type, but with different performance, depending on the operating frequency:

A type	Operating frequency, MHz	Cost, rub.	Speedwork, Aida 64,Memory Read, MB / s
DDR 3	1333	3190	19501
DDR 3	1600	3590	22436
DDR 3	1866	4134	26384
DDR 3	2133	4570	30242
DDR 3	2400	6548	33813
DDR 3	2666	8234	31012
DDR 3	2933	9550	28930

In Aida 64, all DDR 3 tests were performed on identical hardware:

OS: Windows 8.1;
CPU: i5-4670K;
video card: GeForce GTX 780 Ti;
motherboard: LGA1150, Intel Z87.

RAM is very important part of PC that greatly affects its performance. That is why, in order to increase it, it is recommended to set bars with a high frequency and small timings. This will give a big boost in computer performance, it is especially important for games and various professional programs.

Got a question from Alexander Shilin:

People I have such a question, but if I have 600+ written on my mother's ceiling, then 667 strips will go? and then with a frequency of 600, I did not see at all, I saw only 667 and higher.

To be honest, we could not find a motherboard with memory support with an operating frequency of no higher than 600MHz, and 667MHz RAM has almost disappeared from sale.

But we managed to find motherboards with DDR2 667/533/400 support in their specifications, but not a word about DDR2 800. One of such motherboards is ASUS P5LD2 based on Intel 945P chipset.

The chipset is old, and, most likely, when a computer with such a motherboard was assembled, no more than 1GB of memory was installed in it, or even only 512MB. However, the desire to increase computer performance by increasing the amount of RAM has not been canceled.

Only there is no memory in stores with the required characteristics DDR2 667/533/400, but there is only DDR2 800. Can I install it? Will it work?

Can.

To verify this, let's run the CPU-Z program, which I already praised when I wrote about that. Only this time we will open the SPD tab.

Here is an example for DDR2 PC2-5300, 667MHz:

DDR2 PC6400, 800MHz:

And here is the memory, officially marked as DDR2 PC6400, 800MHz, but supporting operation at 1066MHz:

The most interesting line for us in this case is the Frequency line in the Timings Table section. Only the value of the frequency (Frequency) must be multiplied by 2 to get the values \u200b\u200bindicated in the prices and manuals for the mat. boards.

In general, SPD is a system of profiles, hardwired into RAM, which tells the motherboard through the BIOS at what frequency this bar is capable of operating.

And then you can see that DDR2 PC2-5300, 667MHz can operate not only at 667MHz, but also at 533MHz, and even 400MHz.

The same can be said about DDR2 PC6400, 800MHz. The lack of mention of the possibility of working at 667 MHz in the plate is due, I believe, to the economy of space.

I think that the last level will work even at 400 MHz. But from an economic point of view, buying in this case is very strange.

So buy DDR2 PC6400, 800MHz and safely install it on a motherboard supporting only DDR2 667/533/400. Everything will work fine and even more reliably. such a bar will have a tangible margin of safety, instead of working to the limit. 🙂

comments 28

Ilya (Jul 29, 2009 3:56 pm)

On boards supporting only slow memory, you can install fast memory - it just will work on the maximum supported mat. speed fee (i.e. low).

(Jul 29, 2009 4:01 pm)

Ilya, in fact, wrote about this, only in order not to be unfounded, he added several images. 🙂

Anton Young (July 30, 2009, 11:30)

\u003e ASUS P5LD2 on Intel 945P chipset.
I have just such a mother 🙂

\u003e when a computer with such a motherboard was assembled, no more than 1GB of memory, or even only 512MB, was installed in it.
I'm probably ebony. but I have 3GB. I love when memory is LOT.

(Jul 30, 2009, 13:40)

Anton, geeks don't count. 🙂
I was referring to the standard configs that people snatch.

Igor (Aug 27, 2009 00:56 am)

In general, one radish got confused in this memory. The laptop supports 533MHz, there was a 512MB bank duplicate PC4200 worked at 266MHz. Delivered entot PC6400 (800) thought it would work at 533MHz. And it is by no means so - 399 MHz. In short, "clicked" screenshots stuck here: http://komp-kompyuterov.narod.ru/index.html What's there to what? Or everything is correct 400x2 \u003d 800. \u003d)… I’m going to have enlightenment later. Then why fool the people with eight megahertz?

(Aug 27, 2009 7:01 am)

Igor, 800 - this is, obviously, when the two-channel mode is activated: 2 channels of 400 MHz in total give 800.

It's still trickier in the case of laptops. This screenshot clearly shows that the maximum frequency (RAM Max support) is 533MHz. Those. in the case of one bar - 266 MHz.

But you shouldn't be upset. 🙂 2GB is much better than 512MB anyway, and 800MHz is now no more expensive than 533.

Igor (Aug 28, 2009 9:51 am)

Well, at least the issue with "grabbing" from the swap has now been resolved. And it used to slow down not childishly. :)
Well, in short, I did not manage to indulge in innovation enough. A terrible thing happened to the laptop. (My mother didn't spill blood, but ..) By the way, as a result of what happened when trying to open MP3 with Windows MP, he writes that “the operation could not be performed due to lack of memory.” Well, isn't it a mockery? :) And the classic player opens fine. And a lot of bad things are still present. Well this already applies to windows problems or security. Maybe there is a related topic here? Or is it offtopic here? Then I'll leave on the problem globally.

(28 Aug 2009, 09:55)
Igor (Aug 30, 2009 4:06 am)

Well, as they say, once such a piece has gone ... er ... disassembly. 🙂 First, the total of the 1st episode; objects (folders, shortcuts, etc.) seemed to be nailed down and were not moved by any click, “insert” stopped working context menu (always inactive), these same errors were not clicked in the error logs to see the description, when entering accounts empty window without choosing anything, in the task manager the absence of a loved one in the users tab and generally loss of administrator rights, partial or complete xs (message when trying to start an application on drive D), processes in the task manager instead of +50 are 30+ left, periodic reboots with a blue screen (quickly scrolling, you do not have time to see what is written there), later we managed to find out the error code
Error code 10000050, parameter1 8f640cec, parameter2 00000001, parameter3 805b641a, parameter4 00000000.
Error code 10000050, parameter1 c399ff20, parameter2 00000000, parameter3 bf80dd9b, parameter4 00000000.
something like this, when trying to scan for viruses also reboots (in fact, I tried to fight them for 3 days), messages about a dead file system on C, and so on and so on. The main problem was to remove texts with passwords / logins. Already mentally I was ready to rewrite manually, but remembering about the disk with windows, I successfully used the file transfer wizard. how he started manipulating the memory, there was still a hang-up of something, the scandisk well, it went off. I also tried to restore the system - again an error and a reboot. (now I write in the pad and after each sentence Ctrl + S, because the reptile is regularly rebooted :(). Everything described was mixed with the home edishin, the second XP (which was cut off the game edishin) also almost did not start at all, complaining about the broken C. With safe the regime also did not work out sensible. heavy artillery and Acronis True Image Home 11.0 restored sector-by-sector logical C. Everything seemed to work fine (although right now there is such a mess in my head that I can’t guarantee anything :)) And the second axis started working. I changed the memory (goodram) I think the bar was buggy. I inserted it, it seemed like everything was fine in PC Wizard 2008, I even tested it, it showed something like my old 4200. Well, okay, I connected to DSL and let's download new things. The image of the acronis was already in October 2008, albeit with almost all the necessary programs. Well, here I am sitting here stuffing my iron friend ... and bam. Again the old song. Reboot ... mother ... for a long time there was no type. Similar codes, application error log is already corrupted. There was a hang of something (again past my memory :), scandisk pochikal there something. True, this time on the disk of the folder it was not the one where there is 000 at the end.
So I came back after a reboot. :) Some kind of crap I wanted to go to the Internet (it is disabled), I banned it in the chest. Then I went into it to see in more detail what it was, clicked in the log ... error window and reboot. After the error message savedump.exe and now there is no record of this event. Something I really do not know what to think. We can really be a virus. Maybe what stsuka (I'm not holding back anymore) registered in the MBR? Well, the acronis is registered there (recovery at boot). True, launching it with the choice of F11 (recovery) 2-3 times was yesterday, or even now it displays MBR error 2. Can there be something here? In short, everything, no strength. I spread it and go to bed. Tomorrow (today already) I will restore it again with aronis and see how it will develop with old memory... PS By the way, and the mouse on the eve fitted with a double-click button ... Maybe there is something? \u003d)))))) ZYY Zadralo, I can’t come off. Overloaded again. And again some kind of synchronizer of fine soft ones climbed into no. Something like this. ZYYY I could not go in with firelis, I spat, I put my RAM. It seems to hold for some minutes. :) That memory was so hot ... although the laptop was.

Igor (Aug 30, 2009 4:09 am)

What is it like to ban unique content? :) True, I didn't do the paragraphs ...
The peephole test turned out at the same time. :))

(Aug 30, 2009 8:33 am)

Igor, this doesn't look like memory anymore, especially considering its replacement.
It looks like:

1. Virus. It would be nice to boot from some Live CD and check "Dr.Web CureIt!", Since it does not need installation.

2. But it looks even more like death hard disk... Again, it is better to run the check from the Live CD, but in extreme cases, you can just try the Windows one. And look for a utility from the HDD manufacturer.

Igor (Aug 30, 2009 3:49 pm)

3. And it also looks like a poltergeist. :)
In short, memory is a Goodram RAM. Probably some kind of incompatibility. Now, in his native Hyundai Electronics, a real branded Korean, with civilized stamping, everything works without interruptions in the morning. Even from the night - as established. And another system started without problems - I ran it in Perfect World. True, the remaining damage will have to be repaired. For the first time, I returned my memory to a much more dead system, so the result was not visible.
I tested the system without failures. The event log is damaged.
day. The Comodo Firewall is also all right in its log. Dawes-
I installed some updates on the computer and after that there was a development
scuffle. msfeedssync.exe breaks into the network. Firefox using IE
not launched at all. What the hell is it going to check news feeds
or whatever. Well, about the HDD, my health is 88%, but before the crisis it worked fine in my opinion. Maybe he felt bad
when did you fit the new memory? In general, I will restore how
OS, I will update all the rest of the filling and the disk image in the acronis. Then we can still repeat entot gudram, if I don’t give it back before. And I have to think what kind of memory to look for, or rather to find at least something that works for my car. At that point, only this is available on laptops. And we know and use CureIt, since literally half a month ago I picked up “something” (Neshta) and started treating on two computers. Now I checked CureIt - everything is clean.
True, he always swears at Giljabi.exe from my lg_swupdate directory. But I think everything is fine here. :)

Shl Interestingly in memory there can be no virus already packed before me? (type from the manufacturer) :))

Igor (September 1, 2009, 7:30 pm)

Heh, in the confusion, the memory size was not noticed.
in one slot. Now I installed 1GB Kingston and so far everything is ok. And thinking
which will continue to be ok. Now it has become M1 and M2 and not as in the "PC Wizard 2008 physical memory_2Gb" screenshot. With another "M1" Yes
and I remember that I support 2GB, 1GBx2. Those. in two slots.
It remains, on occasion, to put one more in the "bottom" and voila, two-channel
naya. Well, those who have drunk here on the subject will now know what horrors
may follow after a seemingly routine operation.

Sergey (Nov 18, 2009 8:50 pm)

Hello Vladimir! I would be glad to hear your advice.
There is a DDR1 3200 memory stick, 512 MB. Is it better to install another bracket with the same characteristics (DDR1 3200, 512 MB) or a 1 GB bracket (to get 1.5 GB)? By the way, the motherboard (Foxconn P4M800P7MA-RS2) has 2 slots for DDR1 and two slots for DDR2. Does it make sense to install DDR2?

(Nov 18, 2009 8:57 pm)

Sergey, it's better to install another 1GB and get 1.5GB as a result.
You probably won't notice the difference between DDR1 and DDR2, and in most cases it is impossible to install both types of memory at the same time.

Sergey (Nov 19, 2009 9:14 pm)

Thank. And what is the probability that the new 1GB bar will work with the old 512MB? I heard that strips of the same parameters work better with each other, plus a double channel.

Igor (Nov 24, 2009 4:58 pm)

There is absolutely nothing stopping them from working together if the mother supports such a quantity in such slots. Memory needs to be increased for running applications. There will be no significant difference between 1.5 and 2 GB if during the operation of the most capacious one, for example, 1 GB is consumed. The difference will be if it costs 1GB and when the program is running, 1.5 GB is taken, i.e. "Grabs" from swap and, accordingly, slows down due to access to the HDD. Watch: Task Manager-\u003e Performance-\u003e Peak. How much with your favorite heavy machine it is how much RAM you need. \u003d) The two-channel gives an increase of less than 10% if I don't confuse that it is not as important as it is with the above. Well, this is, as they say, my IMHO, although it rules on nubolevel users. \u003d)

Sergey (25 Feb 2010, 00:57)

Artyom (Sep 15, 2010 12:51 pm)

mat. my board is just from the series that is mentioned in this article Asus soket 775 P5LD2 SE. thanks, Vladimir) I'll try.

Anton (Jan 31, 2013 2:05 pm)

Hello, a question of the following nature:
Motherboard ASUS P5LD2 in its description it is written that maximum you can install RAM with a frequency of 667 MHz, but I bought 2 strips of 2 GB and a frequency of 800 MHz, I really liked the computer. used to be 1GB OP.
But after that, the space on the hard disk began to disappear, namely on the "C" drive (it has Windows XP)
Could this be due to a motherboard limitation?
Or did I catch some kind of virus? since at the moment kaspersky without a license well, tobish not paid \u003d does not work.

(Jan 31, 2013 2:09 pm)

Anton, is there a lot of space missing?
Windows has a paging file, it can sometimes depend on the size of the RAM.
There is a sleep mode, when all the contents of the RAM are saved to the hard disk - and the system always reserves the same amount of memory. You can turn it off and the place will return.

Or maybe just some kind of coincidence.

Vas! (May 19, 2013 7:34 pm)

Good! Can you tell me: the Asus motherboard supports memory up to 800 MHz, now it costs 2 x 512 at 533 speeds (pc-4300). Is it possible to expand by delivering 1 or 2 GB but 800th memory. Zs-4300 is nowhere to buy. Will there be such a combination of 2x512MB for 533 and 1 or 2 GB for 800 ??? Thank.

Opana (October 23, 2015 3:43 pm)

Hello, I have slots for DDR3 and DDR4 on my mother, can I stick to 8Gb * 2 [email protected] 8Gb more * 2 [email protected]

Tony (March 27, 2017 4:29 pm)

My question is, will this work in toshiba laptop Satelit A 215? There, the frequency will definitely be 667 hertz at the 800 hertz bar, and is there a risk that it will not start at all? And in general, you can shove more than 4 gigs of RAM there? Or is there 4 - maximum?

a guest (2 July 2018, 10:22)

Ha, P5RD2-VM does not start with 800 memory (officially the ceiling is 667). But she found a crutch - if you stick one 667 together and another 800, then everything works.

Vadim (October 10, 2018 12:08 pm)

asrock 945gcm-s does not support 800MHz memory