What kind of RAM is ddr2. How to distinguish between types of memory SIMM, DIMM, DDR, DDR2, DDR3. What are timings

Here again I was asked how the type of RAM can be determined by its appearance. Because This question pops up from time to time, I decided that it is better to show it once than to explain it a hundred times on the fingers, and write an illustrated mini-review of types of RAM for PC.

Not everyone is interested in this, so I hide it under the cat. To read

The most common types of RAM that have been and are used in personal computers in everyday life are called SIMM, DIMM, DDR, DDR2, DDR3. SIMM and DIMM are unlikely to be found already, but DDR, DDR2 or DDR3 are now installed in most personal computers. So, in order

SIMM

SIMM for 30 contacts. Used in personal computers with processors from 286 to 486. Now it is a rarity. SIMM for 72 contacts. Memory of this type was of two types FPM (Fast Page Mode) and EDO (Extended Data Out).

The FPM type was used on computers with 486 processors and in the first Pentiums until 1995. Then EDO came along. Unlike its predecessors, EDO starts fetching the next block of memory at the same time it sends the previous block to the CPU.

Structurally, they are the same, they can only be distinguished by marking. The staff who supported EDO could work with FPM, but on the contrary, not always.

DIMM

This was the name of the type of memory SDRAM (Synchronous DRAM). Beginning in 1996, most Intel chipsets began to support this kind of memory modules, making it very popular until 2001. Most computers with Pentium and Celeron processors used this type of memory.

DDR

DDR (Double Data Rate) became the development of SDRAM. This type of memory modules first appeared on the market in 2001. The main difference between DDR and SDRAM is that instead of doubling the clock frequency to speed up operation, these modules transfer data twice in one clock cycle.

DDR2

DDR2 (Double Data Rate 2) is a newer version of DDR that should theoretically be twice as fast. For the first time, DDR2 memory appeared in 2003, and the chipsets that support it - in mid-2004. The main difference between DDR2 and DDR is the ability to operate at a significantly higher clock frequency due to design improvements. Outwardly, the number of contacts differs from DDR: it increased from 184 (for DDR) to 240 (for DDR2).

DDR3

Like DDR2 memory modules, they are available in the form of a 240-pin printed circuit board (120 pins on each side of the module), however, they are not electrically compatible with the latter, and for this reason they have a different "key" location.

Finally, there is another type of RAM - RIMM (Rambus). Appeared on the market in 1999. It is based on traditional DRAM, but with a completely redesigned architecture. In personal computers, this type of RAM did not take root and was used very rarely. Such modules were used in the Sony Playstation 2 and Nintendo 64 game consoles.

SIMM for 30 contacts.

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 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 chips 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 a smaller physical size, lower power consumption and, as a result, a 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 develop, 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 value 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 also increased, on which the memory performance not least depends.

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, the timings of the bars are indicated by a three-character combination (for example, 5-5-5), however, the most critical parameter will be just the first number - it always indicates the 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 the generation that preceded it, could transfer data on both cuts, but 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 obsolete 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 the 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, for owners of computers with DDR2 memory, it is most rational to acquire a new type of RAM only with a thorough upgrade with a corresponding one that supports this newest type, and a new motherboard (and even then today it makes sense to upgrade to the level of components that support DDR4 memory: its current price is on a par with DDR3, and the gain 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 it will be enough to install an additional DDR2 2Gb module), and the performance lag with the next generations is completely uncritical.

The minimum prices for RAM modules (only samples of trusted 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.

In this article, we will look at 3 types of modern RAM for desktop computers:

• DDR - is the oldest type of RAM that can still be bought today, but its dawn has already passed, and this is the oldest type of RAM that we will consider. You will have to find far from new motherboards and processors that use this type of RAM, although many existing systems use DDR RAM. The operating voltage of DDR is 2.5 volts (it usually rises when the processor is overclocked), and it is the largest consumer of electricity among the 3 types of memory we are considering.
• DDR2 is the most common type of memory used in modern computers. It is not the oldest, but also not the newest type of RAM. DDR2 is generally faster than DDR and therefore DDR2 has faster data transfer rates than the previous model (the slowest DDR2 model is equal in speed to the fastest DDR model). DDR2 consumes 1.8 volts and, like DDR, usually increases the voltage when the processor is overclocked
• DDR3 - fast and new type of memory. Again, DDR3 is faster than DDR2, and thus the lowest speed is the same as the fastest DDR2. DDR3 uses less power than other types of RAM. DDR3 draws 1.5 volts, and slightly more when overclocked

Table 1: Specifications of RAM according to JEDEC standards

JEDEC - Joint Electron Device Engineering Council (Joint Engineering Council for electronic devices)

The most important characteristic on which memory performance depends is its bandwidth, which is expressed as the product of the system bus frequency by the amount of data transferred per cycle. Modern memory has a 64-bit wide bus (or 8 bytes), so the bandwidth of DDR400 memory is 400 MHz x 8 Bytes \u003d 3200 MB per second (or 3.2 GB / s). Hence, another designation for this type of memory follows - PC3200. Recently, a dual-channel memory connection is often used, in which its bandwidth (theoretical) doubles. Thus, in the case of two DDR400 modules, we will get the maximum possible data exchange rate of 6.4 GB / s.

But the maximum memory performance is also affected by such important parameters as "memory timings".

It is known that the logical structure of a memory bank is a two-dimensional array - the simplest matrix, each cell of which has its own address, row number and column number. To read the contents of an arbitrary cell in the array, the memory controller must set the RAS line number (Row Adress Strobe) and the CAS column number (Column Adress Strobe), from which data is read. It is clear that there will always be some kind of delay (memory latency) between the submission of the command and its execution, and these very timings characterize it. There are many different parameters that determine timings, but the most commonly used four are:

• CAS Latency (CAS) - the delay in clock cycles between the CAS signal and the actual data output from the corresponding cell. One of the most important characteristics of any memory module;
• RAS to CAS Delay (tRCD) - the number of memory bus cycles that must pass after the RAS signal is given before the CAS signal can be applied;
• Row Precharge (tRP) - time of closing a memory page within one bank, spent on recharging it;
• Activate to Precharge (tRAS) - strobe active time. The minimum number of cycles between the activation command (RAS) and the precharge command, which ends with this line, or the closing of the same bank.

If you see the names "2-2-2-5" or "3-4-4-7" on the modules, you can rest assured that these are the parameters mentioned above: CAS-tRCD-tRP-tRAS.

The standard CAS Latency values \u200b\u200bfor DDR memory are 2 and 2.5 clocks, where CAS Latency 2 means that data will be received only two clocks after receiving the Read command. In some systems, the values \u200b\u200b3 or 1.5 are possible, and for DDR2-800, for example, the latest version of the JEDEC standard defines this parameter in the range from 4 to 6 clock cycles, while 4 is an extreme option for selected "overclocking" microcircuits. The latency of RAS-CAS and RAS Precharge is usually 2, 3, 4 or 5 clocks, and tRAS is a little more, from 5 to 15 clocks. Naturally, the lower these timings (at the same clock speed), the higher the memory performance. For example, a module with a CAS latency of 2.5 usually performs better than a module with a latency of 3.0. Moreover, in a number of cases, memory with lower timings turns out to be faster, operating even at a lower clock frequency.

Tables 2-4 provide general DDR, DDR2, DDR3 memory speeds and specifications:

Table 2: Common DDR Memory Speeds and Specifications

Table 3: Common DDR2 Memory Speeds and Specifications

A type	Bus frequency	Baud rate	Timings	Notes
PC3-8500	533	1066	7-7-7-20	more commonly called DDR3-1066
PC3-10666	667	1333	7-7-7-20	more commonly called DDR3-1333
PC3-12800	800	1600	9-9-9-24	more commonly referred to as DDR3-1600
PC3-14400	900	1800	9-9-9-24	more commonly called DDR3-1800
PC3-16000	1000	2000	TBD	more commonly called DDR3-2000

Table 4: Common DDR3 Memory Speeds and Specifications

DDR3 can be called a newcomer among memory models. Memory modules of this kind are only available for about a year. The efficiency of this memory continues to grow, only recently hitting the JEDEC limits, and beyond. Today DDR3-1600 (JEDEC's highest speed) is widely available and more manufacturers are already offering DDR3-1800). DDR3-2000 prototypes are shown on the market today and should go on sale later this year - early next year.

The percentage of DDR3 memory modules entering the market, according to manufacturers, is still small, in the range of 1% -2%, which means that DDR3 has a long way to go before it matches DDR sales (still within 12% - 16%) and this will allow DDR3 to get closer to DDR2 sales. (25% -35% in terms of manufacturers).

DDR and DDR2 memory modules "\u003e

DDR2 is the successor to DDR. It is likely that DDR2 will become the dominant type for desktops, servers, and workstations over the coming year. DDR2 is designed to operate at higher frequencies than DDR, it is characterized by lower power consumption and a set of new functions (4-bit prefetch, deferred CAS, built-in termination, external shaper calibration). Besides, unlike DDR chips, which were produced both in TSOP and FBGA packages, DDR2 chips are produced only in FBGA packages (this is necessary for stable operation at high frequencies).

DDR SDRAM chip in TSOP package	DDR2 SDRAM chip in BGA package

The JEDEC DDR2 specification was released on September 12, 2003.

The memory operating at 200 MHz and 266 MHz is called DDR2 400 and DDR2 533, respectively. DDR2 667 and DDR2 800 are expected to be released later.

Memory type	Frequency	Bandwidth for single channel memory	Bandwidth for dual channel memory
DDR266 (PC2100)	133 MHz DDR	2100 Mb / s	4200 Mb / s
DDR333 (PC2700)	166 MHz DDR	2700 Mb / s	5400 Mb / s
DDR400 (PC3200)	200 MHz DDR	3200 Mb / s	6400 Mb / s
DDR2 400 (PC2 3200)	200 MHz DDR	3200 Mb / s	6400 Mb / s
DDR2 533 (PC2 4300)	266 MHz DDR	4266 Mb / s	8533 Mb / s
DDR2 667 (PC2 5300)	333 MHz DDR	5333 Mb / s	10666 Mb / s
DDR2 800 (PC2 6400)	400 MHz DDR	6400 Mb / s	12800 Mb / s

History random access memory, or RAM, began back in 1834, when Charles Babbage developed the "analytical engine" - in fact, the prototype of the computer. The part of this machine, which was responsible for storing intermediate data, he called the "warehouse". Memorization of information there was organized in a purely mechanical way, by means of shafts and gears.

In the first generations of computers, cathode-ray tubes and magnetic drums were used as RAM, later magnetic cores appeared, and after them, in the third generation of computers, memory on microcircuits appeared.

Now RAM is performed using technology DRAM in form factors DIMM and SO-DIMM, it is a dynamic memory organized in the form of semiconductor integrated circuits. It is volatile, meaning that data disappears when there is no power.

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

Memory types

SO-DIMM

Memory of the form factor SO-DIMM is intended for use in laptops, compact ITX-systems, all-in-ones - in short, where the minimum physical size of memory modules is important. It differs from the DIMM form-factor with a reduced module length by about 2 times, and a smaller number of pins on the board (204 and 360 pins for SO-DIMM DDR3 and DDR4 versus 240 and 288 on boards of the same types of DIMM memory).
In terms of other characteristics - frequency, timings, volume, SO-DIMM modules can be any, and they are no different from DIMMs.

DIMM

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

DDR memory appeared in 2001, and had 184 contacts. The supply voltage was from 2.2 to 2.4 V. The operating frequency was 400 MHz. It is still found on sale, however, the choice is small. Today the format is outdated - it is suitable only if you do not want to update the system completely, and in the old motherboard there are only DDR connectors.

The DDR2 standard came out in 2003, received 240 pins, which increased the number of threads, decently speeding up the data transfer bus to the processor. The DDR2 operating frequency 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 lower than that of DDR. Consequently, the power consumption and heat dissipation of memory have decreased.
Differences between DDR2 and DDR:

240 pins versus 120
New slot not compatible with DDR
Less power consumption
Improved design, better cooling
Higher maximum operating frequency

Also, like DDR, the outdated type of memory is now suitable only for old motherboards, in other cases it makes no sense to buy, since the new DDR3 and DDR4 are faster.

In 2007, the RAM was updated with the DDR3 type, which is still widely used today. The same 240 pins remain, but the connection slot for DDR3 has changed - there is no DDR2 compatibility. The frequency of the modules is on average from 1333 to 1866 MHz. There are also modules with frequencies up to 2800 MHz.
DDR3 differs from DDR2:

· DDR2 and DDR3 slots are not compatible.
· The clock frequency of DDR3 is 2 times higher - 1600 MHz versus 800 MHz for DDR2.
Differs in a reduced supply voltage - about 1.5V, and lower power consumption (in the versionDDR3L this value is even lower on average, about 1.35 V).
· The latencies (timings) of DDR3 are higher than those of DDR2, but the operating frequency is higher. In general, the speed of DDR3 is 20-30% higher.

DDR3 is a good choice today. In many motherboards, DDR3 memory slots are on sale, and due to the massive popularity of this type, it is unlikely to disappear soon. It is also slightly cheaper than DDR4.

DDR4 is a new type of RAM that was only developed in 2012. It is an evolutionary development of the previous types. Memory bandwidth has improved again, now reaching 25.6 GB / s. The operating frequency has also increased - from an average of 2133 MHz to 3600 MHz. If we compare the new type with DDR3, which held out on the market for 8 years and became widespread, then the performance gain is insignificant, and besides, not all motherboards and processors support the new type.
DDR4 Differences:

Incompatibility with previous types
Reduced supply voltage - from 1.2 to 1.05 V, power consumption also decreased
Working memory frequency up to 3200 MHz (it can reach 4166 MHz in some trims), while, of course, proportionally increased timings
May slightly outperform DDR3

If you already have DDR3 strips, then there is no point in rushing to change them to DDR4. When this format spreads massively, and all motherboards already support DDR4, the transition to the new type will happen by itself with the update of the entire system. Thus, we can summarize that DDR4 is more of a marketing than a really new type of RAM.

What memory frequency should I choose?

Frequency selection should be started by checking the maximum supported frequencies by your processor and motherboard. It makes sense to take a frequency higher than that supported by the processor only when overclocking the processor.

Today, you shouldn't choose memory with a frequency below 1600 MHz. The 1333 MHz variant is acceptable in the case of DDR3, if these are ancient modules not lying around at the seller, which will obviously be slower than the new ones.

The best option for today is memory with a frequency range from 1600 to 2400 MHz. A higher frequency has almost no advantage, but it costs much more, and as a rule, these are overclocked modules with raised timings. For example, the difference between the 1600 and 2133 MHz modules in a number of working programs will be no more than 5-8%, in games the difference may be even less. Frequencies of 2133-2400 MHz are worth taking if you are engaged in video / audio encoding, rendering.

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

How much RAM to take?

The amount that you need depends on the type of work performed on the computer, on the installed operating system, on the programs used. Also, do not overlook the maximum amount of memory supported by your motherboard.

Volume 2 GB - for today, it may be enough only to browse the Internet. More than half will be consumed by the operating system, the rest will be enough for the leisurely work of undemanding programs.

Volume 4 GB - suitable for a medium-sized computer, for a home pc media center. Enough to watch movies and even play undemanding games. Modern - alas, will hardly pull. (Best choice if you have a 32-bit Windows operating system that sees no more than 3GB of RAM)

Volume 8 GB (or a set of 2x4GB) - the recommended volume for today for a full-fledged PC. This is enough for almost any games, for working with any resource-demanding software. The best choice for a general purpose computer.

A volume of 16 GB (or sets of 2x8GB, 4x4GB) - will be justified if you work with graphics, heavy programming environments, or constantly render video. It is also perfect for online streaming - there may be freezes with 8 GB, especially with high quality video broadcast. Some games in high resolutions and with HD textures can perform better with 16GB of RAM on board.

Volume 32 GB (a set of 2x16GB, or 4x8GB) - so far a very controversial choice, it will be useful for some very extreme work tasks. It would be better to spend money on other computer components, this will have a stronger effect on its performance.

Operating modes: is it better 1 memory stick or 2?

RAM can operate in one-channel, two-, three- and four-channel modes. Definitely, if your motherboard has a sufficient number of slots, then it is better to take several of the same smaller size instead of one memory stick. The access speed to them will increase from 2 to 4 times.

For the memory to work in dual-channel mode, you need to install strips in slots of the same color on the motherboard. Typically, the color is repeated across the connector. It is important that the memory frequency in the two strips is the same.

- Single chanell Mode - single-channel operation mode. It turns on when one memory stick is installed, or different modules operating at different frequencies. As a result, the memory operates at the frequency of the slowest bar.
- Dual Mode - two-channel mode. Works only with memory modules of the same frequency, increases the speed of work by 2 times. Manufacturers release specially for this a set of memory modules, which can have 2 or 4 identical strips.
- Triple Mode - works on the same principle as two-channel. Not always faster in practice.
- Quad Mode - four-channel mode, which works on the principle of two-channel, thus increasing the operating speed by 4 times. It is used where extremely high speed is needed - for example, in servers.

- Flex Mode- a more flexible version of the two-channel operation mode, when the strips are of different sizes, and only the same frequency. In this case, the same volumes of modules will be used in the two-channel mode, and the remaining volume will function in the single-channel mode.

Does the memory need a heatsink?

Now is not the time when at a voltage of 2 V the operating frequency of 1600 MHz was reached, and as a result a lot of heat was released, which had to be removed somehow. Then the radiator could be a criterion for the survival of an overclocked module.

Nowadays, the memory power consumption has dropped significantly, and the heatsink on the module can be justified from a technical point of view only if you are fond of overclocking, and the module will work for you at frequencies beyond its limits. In all other cases, radiators can be justified, perhaps, by a beautiful design.

If the radiator is massive and noticeably increases the height of the memory bar, this is already a significant disadvantage, since it can prevent you from installing a processor supercooler into the system. By the way, there are special low-profile memory modules designed for installation in compact cases. They are somewhat more expensive than regular-sized modules.

What are timings?

Timings, or latency (latency) - one of the most important characteristics of random access memory, which determines its performance. Let us outline the general meaning of this parameter.

Simplified, random access memory can be represented as a two-dimensional table in which each cell carries information. Cells are accessed by specifying the column and row numbers, and this is indicated using the strobe pulse of the row access RAS(Row Access Strobe) and column access strobe CAS (Acess strobe) by changing the voltage. Thus, for each cycle of work, calls occur RAS and CAS, and between these calls and the read / write commands, there are certain delays, which are called timings.

In the description of the RAM module, you can see five timings, which for convenience are written in a sequence of numbers separated by 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 the CAS
· CL (time of CAS Latency) - timing that determines the delay between the read / write command and the CAS pulse
· tRP (time of Row Precharge) - timing that determines the delay in 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 work with it; considered the main value
· Command rate- defines the delay between the command to select a separate chip on the module until the command to activate the line this timing is not always indicated.

To put it even simpler, it is important to know only one thing about timings - the lower their values, the better. At the same time, the bars can have the same operating frequency, but different timings, and the module with lower values \u200b\u200bwill always be faster. So it is worth choosing the minimum timings, for DDR4 the average values \u200b\u200bwill be 15-15-15-36, for DDR3 - 10-10-10-30. It is also worth remembering that the timings are related to the memory frequency, so during overclocking, you will most likely have to raise the timings, and vice versa - you can manually lower the frequency, while lowering the timings. It is most advantageous to pay attention to the totality of these parameters, choosing a balance rather, and not to chase the extreme values \u200b\u200bof the parameters.

How do you decide on a budget?

With more money, you can afford more RAM. The main difference between cheap and expensive modules will be in the timings, frequency of operation, and in the brand - well-known, advertised ones can cost a little more than noname modules of an unknown manufacturer.
In addition, a radiator installed on the modules costs extra money. Not all bars need it, but manufacturers are now not stingy with them.

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

So, having up to 2000 rubles, you can buy a 4 GB memory module, or 2 2 GB modules, which is preferable. Choose whichever allows your pc's configuration. DDR3 modules will cost almost half as much as DDR4. With such a budget, it makes more sense to take DDR3.

To the group up to 4000 rubles includes modules with a volume of 8 GB, as well as sets of 2x4 GB. It is the optimal choice for any task, except for professional video work, and in any other difficult environment.

In the amount up to 8000 rubles will cost 16 GB of memory. Recommended for professional purposes, or for avid gamers - enough even in reserve, in anticipation of new demanding games.

If it's not a problem to spend up to 13,000 rubles, the best choice would be to put them in a set of 4 x 4GB sticks. For this money, you can even choose prettier radiators, possibly for subsequent overclocking.

I do not recommend taking more than 16 GB without the purpose of working in professional heavy environments (and even then not in all), but if you really want to, then for the amount from 13000 rubles you can climb Olympus by purchasing a 32GB or even 64GB kit. True, there won't be much sense for an ordinary user or gamer in this - it's better to spend money on, say, a flagship video card.