RAM– one of the most important components of the system, on which the performance of the computer directly depends.
In the catalog you can select and buy RAM of a suitable type with a capacity from 1 to 32 GB, single sticks, as well as KIT memory modules of 2 and 4 sticks complete with the same characteristics, selected for working in pairs (dual-channel mode). Using dual-channel mode leads to a significant increase in throughput, and, consequently, an increase in application speed. For compact systems, low-profile memory modules are available that differ from standard ones in height, but not in performance. While for outdated platforms, regular and server RAM modules of the Registered DDR, DDR2, Registered DDR2 and DDR2 FB-DIMM standards are presented. Affordable prices for RAM of these standards make the choice obvious when looking to replace faulty memory or expand the existing total memory capacity in the system.
Today, the most common type of memory for desktop PCs based on Intel and AMD is DDR3 RAM. However, Low Voltage (LV DDR3) is not supported by all motherboards and processors. Suitable for the most modern processors. It is distinguished by a maximum data transfer rate doubled to 3.2 Gbit/s, increased to 4266 MHz
maximum frequency and unsurpassed stability. The increased number of pins makes DDR4 modules incompatible with older slots. The higher the clock frequency, the more operations are performed per unit of time, which allows for more stable and faster work
computer games and other applications. Prices for RAM with high clock speeds are, of course, higher. But before you buy memory, pay attention to what maximum frequency is indicated in the processor description. Using memory with frequencies higher than the declared values will not give a noticeable increase in performance. If you are collecting and, if possible, less delays.
Prices for gaming memory are not the lowest, but in this case the system performance will be higher than when using standard memory sticks. The decoration of any gaming PC will be backlit. White or multi-color backlighting does not affect performance, but it looks very stylish and relevant for a PC of this class. Fast memory modules are distinguished by the presence of profiles that expand the capabilities of SPD. The most popular at the moment is the so-called. XMP support allows you to overclock DDR3 and DDR4 memory and thus achieve even more high performance
and improve gaming functionality without complex changes in memory voltage and frequency.
How to choose RAM (RAM, DDR), which memory module is better When choosing RAM (RAM, DDR) for upgrading a computer, or assembling a new one, most users pay little attention to the quality and type of RAM modules. The “only parameter” of RAM is often its capacity, but this is far from the only parameter that you need to pay attention to when choosing. And so, let's consider basic RAM parameters
, and what depends on them.
Form factor For desktop computer , the form factor (standards and physical dimensions) will be DIMM , and for a laptop.
SODIMM
Well, now let's get down to the characteristics...
Amount of RAM and number of memory modules
As stated earlier, this is the first criterion for selection. When choosing the volume of RAM modules and their quantity, you must first of all clearly understand for what purposes the computer will be used. If this is a computer for office tasks or surfing the Internet, then it does not need a large amount of RAM, and today, for such a computer, it will be enough 2GB
one module. If your computer is a gaming station, or work station with applications that consume a large amount of RAM, it would be advisable to purchase
4 - 8 GB Number of RAM modules significantly affects PC performance. Here, for example, the same computer with the same amount of RAM, but with big amount memory modules (for example, the first one has 4GB with one stick, and the second one has 2 sticks of 2GB each) will load the game faster than the first one. "Why is that?" - you ask, but because modern motherboards, just like memory controllers in processors, have support. By installing 2 or 3 RAM sticks in the corresponding slots of the motherboard (to activate this mode, the sticks must be inserted into slots of the same color), you will activate two or three channel mode, which in theory can increase the total memory bandwidth by 2 or 3 times, respectively ( in practice it is much less, but the difference is significant). For example, if one memory module has a bus width of 64 bits, this means that the processor can read 64 bits from memory in one clock cycle, and the number of clock cycles corresponds to the operating frequency of the RAM. And when you set two or three channel mode, you thereby increase the bus width by 2 (128 bits) or 3 (192 bits) times.
But there are also pitfalls here; you shouldn’t immediately rush to buy several RAM modules if this performance gain does not play a big role for you. By installing two or three channel mode, you may reduce the stability of the computer, since the likelihood of errors in such modes is much higher than in single-channel mode. This depends on many factors: operating frequency, manufacturer, timings, whether the memory modules that need to work together are the same, etc. Moreover, from my experience in computer repair, there are many cases when, after 3 - 4 years of uninterrupted operation in dual-channel mode, the motherboard (chipset) gradually (and sometimes abruptly) stops working correctly in this mode, or does not start at all (the latter option is more frequent) reporting the absence of memory modules. But as soon as all the modules except one were pulled out, the system magically began to work. Decide this problem It was possible by installing two modules on one channel (of different colors), and “throwing out” the remaining modules (if there were any). Or you could warm up the chipset/processor (depending on where the memory controller is) - this could help for a short period of time. The reason why the memory controller fails, as well as the quality of the modules themselves deteriorates, is chip degradation.
Memory should be purchased based on the recommendations of the manufacturer of your computer’s motherboard. To do this, just go to the manufacturer’s website, find your board there, and find the section with supported modules and memory manufacturers. A motherboard can, of course, work wonderfully with other memory modules, but still, by purchasing memory from the list of supported ones, you guarantee stable operation.
Memory type and memory frequency
The type of RAM primarily indicates technical process, according to which the chips are made, and indicates that the newer module operates at a higher frequency, which has a positive effect on performance.
At the moment, there are 2 types of memory - DDR2 and DDR3, to buy a new computer, I think the choice is obvious - take only the new one, and this is DDR3 (at the time of writing). To upgrade your computer, you don’t have much of a choice; you’ll have to take the memory that your motherboard supports. Only in some cases, when upgrading a computer, you can change the memory to a newer one. But this is only possible if you have a “combo” motherboard that supports both older and older new type memory, but together, modules different types will not work, and if you have older memory installed, you will have to “throw it out” and put newer memory in other slots.
The frequency of RAM can be different; even sticks of the same type can have different frequencies. Ideally, it is advisable to choose memory with a frequency identical to the processor FSB bus. And do not confuse the effective frequency of RAM operation with the effective one. For example, DDR 1333 memory is DDR2 class memory and operates at a REAL frequency of 667 MHz. The FSB bus of the processor is also described as effective, and it must be divided by 2 to determine the real one.
Memory delays (timings)
Memory timings or memory latency are time delays in a signal. Memory latencies in some way affect the performance (bandwidth and access speed) of the RAM module as a whole. The lower the memory latency, the faster it can run. Memory timings are usually written in the form 2-2-2-6, each part of the recording corresponds to the signal delay of each of the main parameters. We won’t go into the details of how each process works right now, you just need to know that the lower the memory timings, the more productive it is (up to 10%).
For modern memory modules, its timings are not the main criterion, since processors working with DDR3 memory have a relatively large second- and third-level memory cache, which can significantly reduce the number of memory accesses and, in turn, reduces the value of memory latencies. But despite this, timings still matter and cannot be ignored when choosing a memory module.
RAM module manufacturer
The stability, quality, and to some extent performance of RAM directly depend on the manufacturer. Not all RAM manufacturers make high-quality memory modules, and as a rule, a high-quality memory module costs a little more than others. I will list several well-known and good memory manufacturers at the moment: Transcend, Samsung, Kingston, OCZ. These are not the only manufacturers who do good memory, but when buying memory from these manufacturers you do not risk buying a pig in a poke.
Overclocking
Most well-known manufacturers have overclocked RAM models. This undoubtedly gives an increase in performance, but you shouldn’t overpay significantly for it, since you can overclock the RAM yourself. And besides, this will lead to her death faster due to chip degradation. But if you still decide to choose an overclocked module, then please note that these memory modules must have cooling.
Cooling
If you plan to overclock your computer, including RAM, then it is advisable to choose a memory module that has cooling in the form of aluminum plates.
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Greetings, dear readers! Today I will talk about the types of computer RAM. There are many varieties of it - enough to get confused in the parameters.
From this article you will learn:
A brief excursion into history
A long time ago, when computers were large, programs were small, and viruses did not exist at all, SIMM modules of several modifications were used: 30, 68 and 72 pins. They worked in conjunction with processors from 286 to 486 inclusive.
Now it is extremely difficult to find such a computer in working condition: there is no modern software for it. Programs that could theoretically be launched turn out to be too cumbersome in practice.
DIMM
The main difference from its predecessor is that the contacts located on both sides of the strip are independent, unlike the paired contacts on SIMM. SDRAM technology is already involved here - synchronous dynamic random access memory. 
Mass production of this type of memory began in 1993. Such modules were intended primarily for the Intel Pentium or Celeron processor on a 64-bit data bus.
SO-DIMM memory modules are more compact as they are used in laptops.
DDR
More precisely, this type of memory is correctly called DDR SDRAM. It appeared on the market in 2001 and was used as RAM and video memory. The difference from its predecessor is the doubled frequency, since the bar is capable of transmitting data twice in one clock cycle.
This is the first type of memory module that can operate in dual-channel mode.
You can find out more about what dual-channel mode is.
And so yes, DDR SDRAM and its descendants are produced in the DIMM form factor, that is, they have independent contacts on both sides.
DDR2
This type of memory was able to compete with its predecessor already in 2004 and occupied a leading position until 2010. The sticks were produced in DIMM form factors for desktop computers and SO-DIMM for portable ones.
Compared to its predecessor, this type of memory has:
- Greater throughput;
- Less energy consumption;
- Improved cooling due to design.
The disadvantages include higher RAM timings. What it is .
DDR3
Like its predecessor, they are produced in the form of a 240-pin strip, but are incompatible due to different connectors (I’ll talk about this in more detail later).
The memory type is characterized by an even higher frequency and lower power consumption, as well as an increase in pre-swapping from 4 to 8 bits. There is a DDR3L modification with an operating voltage reduced to 1.35 V. By the way, about frequency. There are several modifications: 1066, 1333, 1600, 1866, 2133 or 2400 with the corresponding data transfer speed. 
Produced since 2012. Computers using this type of memory are still in use today. The volume of installed modules is from 1 to 16 GB. In the SO-DIMM form factor, the “ceiling” is 8 GB.
DDR4
The fourth generation doubled the number of internal banks, thereby increasing the transfer speed of the external bus. Mass production began in 2014. Top models throughput reaches 3200 million transfers per second, and they are produced in modules with capacities from 4 to 128 GB.
They already have 288 contacts. The physical dimensions of the part are the same, so the connectors are packed more tightly. Compared to DDR3, the height has been slightly increased. 
SO-DIMMs have 260 pins located closer together.
What's next?
An interesting trend: with each next generation of memory, the timings increase, which engineers try to compensate for by increasing the operating frequency and data transfer speed. So effective that the next generation turns out to be faster than its predecessors.
That is why I once again draw your attention to the fact that when choosing components, try to “dance” from the DDR4 standard as the newest and most progressive.
Memory type compatibility
There is a misconception that, due to the interface features, it is impossible to insert a memory stick into unsuitable slots. I will say this: a strong enough guy (and even some girls) will insert anything anywhere - not only RAM, but also Intel processor into the AMD slot. True, there is one BUT: such an assembly, alas, will not work.
Other users who carefully assemble computers usually cannot insert the RAM into the wrong slot. Even if the planks have the same dimensions, this will not allow making a so-called key. There is a small protrusion inside the slot that prevents mounting the wrong type of RAM. The appropriate strip has a small cutout in this place, so you can insert it without any problems.
How to determine the model
The utilities built into Windows allow you to find out only minimal information - the volume installed memory. It is impossible to find out what type it is this way. Third-party software will come to the rescue, issuing full information about the system - for example, Everest or AIDA64.
The memory type is also specified in the BIOS. Where exactly this information is indicated and how to call the BIOS depends on its modification. In most cases, it is enough to hold down the Del button when starting the computer, but exceptions are possible.
Naturally, the marking is indicated on the RAM itself, or rather on the glued nameplate. To get to the bar, you will have to disassemble the case and dismantle it. In the case of a laptop, this simple task turns into a fascinating quest with viewing detailed instructions for disassembly.
Here, in fact, is all about the types of RAM, which is enough to know to independently select components. And if you are building a gaming computer, I recommend that you read the information.
Thank you for your attention and see you next time! Don't forget this blog and share posts on social networks.
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 ones 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 (usually increases when the processor is overclocked), and is the largest consumer of electricity among the 3 types of memory we are considering.
- DDR2- This is the most common type of memory used in modern computers. This is not the oldest, but not the newest type of RAM. DDR2 is generally faster than DDR, and therefore DDR2 has a data transfer speed greater 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, the voltage usually increases when overclocking the processor
- DDR3- fast and new type of memory. Again, DDR3 is faster than DDR2, and thus the slowest speed is the same as the fastest DDR2 speed. DDR3 consumes less power than other types of RAM. DDR3 consumes 1.5 volts, and a little more when overclocking the processor
Table 1: Specifications RAM according to JEDEC standards
JEDEC- Joint Electron Device Engineering Council
The most important characteristic on which memory performance depends is its bandwidth, expressed as the product of the system bus frequency and the amount of data transferred per clock cycle. Modern memory has a bus width of 64 bits (or 8 bytes), so the bandwidth of DDR400 memory is 400 MHz x 8 Bytes = 3200 MB per second (or 3.2 GB/s). Hence, another designation for memory of this type follows - PC3200. Recently, dual-channel memory connections are often used, in which its (theoretical) bandwidth is doubled. Thus, in the case of two DDR400 modules, we will get the maximum possible data transfer speed of 6.4 GB/s.
But on maximum performance memory 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 array cell, the memory controller must specify the RAS (Row Adress Strobe) row number and the CAS (Column Adress Strobe) column number, from which the data is read. It is clear that there will always be some kind of delay (memory latency) between issuing a command and its execution, which is what these timings characterize. There are many different parameters that determine timings, but the four most commonly used are:
- CAS Latency (CAS) - the delay in clock cycles between the application of the CAS signal and the direct output of data from the corresponding cell. One of the most important characteristics of any memory module;
- RAS to CAS Delay (tRCD) - the number of memory bus clocks that must pass after the RAS signal is applied before the CAS signal can be applied;
- Row Precharge (tRP) - the time it takes to close a memory page within one bank, spent on recharging it;
- Activate to Precharge (tRAS) - strobe activity time. The minimum number of cycles between the activation command (RAS) and the recharging command (Precharge), which ends work with this line, or closing the same bank.
If you see the designations “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.
Standard CAS Latency values for DDR memory are 2 and 2.5 clock cycles, where CAS Latency 2 means that data will be received only two clock cycles after receiving the Read command. In some systems, values of 3 or 1.5 are possible, and for DDR2-800, for example, latest version The JEDEC standard defines this parameter in the range from 4 to 6 clock cycles, while 4 is an extreme option for selected “overclocker” chips. The latency of RAS-CAS and RAS Precharge is usually 2, 3, 4 or 5 clock cycles, while tRAS is slightly longer, from 5 to 15 clock cycles. Naturally, the lower these timings (at the same clock frequency), the higher the memory performance. For example, a module with a CAS latency of 2.5 typically performs better than one with a latency of 3.0. Moreover, in a number of cases, memory with lower timings, operating even at a lower clock frequency, turns out to be faster.
Tables 2-4 provide general DDR, DDR2, DDR3 memory speeds and specifications:
Table 2: General DDR Memory Speeds and Specifications
Table 3: General DDR2 Memory Speeds and Specifications
| Type | Bus frequency | Data transfer 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 often called 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 type have only been available for about a year. The efficiency of this memory continues to increase, only recently reaching the JEDEC limits, and beyond these limits. Today, DDR3-1600 (JEDEC's highest speed) is widely available, and more manufacturers are already offering DDR3-1800). DDR3-2000 prototypes have been shown on the current market and should go on sale late this year or 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 in the range of 12%- 16%) and this will allow DDR3 to approach DDR2 sales. (25%-35% according to manufacturers’ indicators).
