Type of RAM, which determines the main characteristics of memory and internal structure. Today there are five main types of RAM: SDRAM, DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM, RIMM.
SDRAM is synchronous dynamic memory with random access. Advantages compared to older generations of memory: synchronization with the system oscillator, this allows the memory controller to know the specific time the data is ready, with this innovation time delays during sleep cycles are reduced due to the fact that data is free to be accessed during each clock cycle timer. Previously, SDRAM was actively used in computers, but has now been almost completely replaced by DDR and DDR2.
DDR SDRAM is a synchronous dynamic memory that has random access and is characterized by double the information transfer rate. Advantages of DDR SDRAM over SDRAM: in one cycle of the system generator, two operations with information can be performed, which doubles the peak throughput when operating at the same frequency.
DDR2 SDRAM is the next generation of memory after DDR. The operating principle is similar to that used in DDR. Difference: it is possible to sample 4 bits of data in one clock cycle (for DDR 2-bit sampling is performed), the operating frequency is increased, the power consumption of memory modules is reduced, and heat dissipation is reduced.
DDR3 SDRAM is the next generation of DDR2 SDRAM memory, the same “frequency doubling” technology is used. The main difference from DDR2: the ability to operate at a higher frequency. DDR3 modules have 240 pads, but they are not compatible with older slots because they use different orientation slots (“keys”).
RIMM (Rambus DRAM, RDRAM) is a synchronous dynamic memory developed by Rambus. The main differences from DDR memory: increasing the clock frequency by reducing the bus width, simultaneous transmission of the column and cell row numbers when accessing memory. RDRAM costs significantly more than DDR, and with similar performance, this has led to the fact that this type memory has almost completely left the market.
When deciding on the type of memory, focus primarily on the capabilities of your computer’s motherboard, as well as its compatibility with different memory modules.

Form factor
RAM module standard. The form factor (standard) determines the dimensions of the memory module, as well as the number of contacts and their location. There are several completely incompatible memory standards: SIMM, DIMM, FB-DIMM, SODIMM, MicroDIMM, RIMM.
SIMM - memory modules of this standard often have 72 or 30 contacts, each of these contacts is equipped with an output on two sides of the memory board.
DIMM - memory modules of the DIMM standard, usually they have 240, 200, 184 or 168 independent pads, the pads are located on two sides of the memory board.
DDR2 FB-DIMM - memory modules of this standard are used in servers. They are mechanically similar to 240-pin DIMMs, but are completely incompatible with regular unbuffered Registered DDR2 DIMMs and DDR2 DIMMs.
SODIMM is a compact version of DIMM, usually used in Tablet PCs and laptops. Most often it has 72, 144, 168, 200 contacts.
MicroDIMM is one of the DIMM options for subnotebooks and laptops. Dimensions are smaller than SODIMM, characterized by the presence of 60 contact pads.
RIMM is a standard for RIMM-type memory modules (RDRAM), characterized by the presence of 184, 168 or 242 contacts.
The standard of the RAM module and the standard that the motherboard supports must match.

Volume of one module
from 0.03125 to 128 GB
The amount of memory that one module has. The total memory capacity of the system can be calculated by adding up the memory capacity of all installed modules. For comfortable work in office programs and the Internet is enough for 512 MB. For normal operation with office applications, and also with graphic editors 1 GB (1024 MB) of RAM is enough. Work in difficult graphics programs 2 GB (2048 MB) of system memory will allow you to play computer games.

Number of modules
from 1 to 16
The number of memory modules sold in a set. There are not only single strips on sale, but also sets; a set can contain two modules, four, six, eight, all of them have identical characteristics and are selected for operation in two-channel mode (in pairs). The use of such a dual-channel mode allows you to achieve a noticeable increase in throughput, and, as a result, an increase in the speed of applications. It must be said that the fact that you bought two modules from the same manufacturer that have the same characteristics does not mean at all that they will be able to operate in dual-channel mode. For this reason, if the motherboard of your computer is capable of supporting dual-channel memory mode, then you should turn your attention to kits consisting of several modules, if, of course, it is important for you high speed operation of graphic and gaming applications.

Number of contacts
from 144 to 288
The number of contact pads located on the memory module. The number of contacts on the module must match the number of contacts in the RAM slot located on motherboard. It must be remembered that in addition to the same number of contacts, the “keys” must also match (the “keys” are the cutouts on the module; they eliminate the possibility of incorrect installation).

Number of ranks
from 1 to 8
The number of memory areas (ranks) of the RAM module. A rank is a memory area that is formed by several chips or all chips of a memory module and has a width of 64 bits. The RAM module, depending on the design, can have one, two or four slots. Server motherboards produced today are characterized by the presence of a limitation on the total number of memory ranks, for example, if a maximum of eight ranks can be installed and four two-rank modules are already installed, then install additional modules it will no longer work in free slots, because installing them will cause the limit to be exceeded. This is why single-rank modules are more expensive than two- and four-rank modules.

Clock frequency
from 66 to 4800 MHz
The lowest frequency of the system generator; it is used to synchronize the processes of receiving and transmitting information. For DDR, DDR2 and DDR3 memory, the clock frequency is doubled (two data operations are performed in one clock cycle). The higher the clock frequency, the large quantity operations per unit of time can be performed, this allows computer games and other applications work more stable and faster. With all other identical characteristics, memory with a higher frequency costs more.

Bandwidth
from 1600 to 38400 Mb/s
The bandwidth of a memory module is the amount of information received or transmitted in one second. This parameter is directly dependent on the memory clock frequency. The bandwidth of a memory module is calculated by multiplying the bus width by the clock frequency. The greater the bandwidth, the greater the memory speed, the higher the price of the module (if other characteristics are the same).

ECC support
Support for ECC (Error Checking and Correction) algorithm, which makes it possible to both identify and correct errors that occur accidentally during data transmission (no more than one bit per byte). Almost all server boards, as well as some workstation motherboards, can support Error Checking and Correction technology. Memory modules with ECC are more expensive than those that do not support this algorithm.

Buffered (Registered)
The presence of a buffer (special registers) on the memory module, special registers can quickly save incoming data, reduce the load on the synchronization system, thereby freeing up the memory controller. The presence of special registers between the memory chips and the controller leads to an additional delay of one clock cycle when performing operations, thus, higher reliability occurs due to a slight decrease in performance. Memory modules equipped with registers are characterized by high cost; they are mainly used in servers. It should be remembered that unbuffered and buffered memory are incompatible, which means that their simultaneous use in the same system is impossible.

Low Profile
A memory module that is characterized by a smaller height (compared to the standard size). This size makes it possible to install it in low server cases.

Radiator
The presence of special metal plates attached to memory chips; these plates are designed to improve heat transfer. Heatsinks are usually installed on memory modules that operate at high frequencies.

XMP support
XMP (eXtreme Memory Profiles) – a profile containing data about the expanded and non-standard capabilities of the RAM module. Affordable Computer BIOS During the initial loading period, the system switches to overclocking mode, without manually setting all operating delays.

Timings

from 2 to 22
CAS Latency, CAS - the number of clock cycles from the time of requesting data to reading it from the memory module. CAS Latency, CAS – the most important characteristic memory module, it will determine the performance of the memory. As the number of CLs decreases, memory performance speeds up.

tRCD
from 2 to 26
RAS to CAS Delay is the delay between the signals that determine the column address and the row address.

tRP
from 2 to 26
Row Precharge Delay. This parameter determines the period of charge accumulation, recharging of the RAS signal (re-dispensing time), i.e. the time after which the memory controller will again be able to issue a signal to initialize the row address.

tRAS
from 5 to 52
Activate to Precharge Delay is the smallest number of cycles between RAS (activation command) and Precharge (recharge command) or closing of the same memory bank.

Additional Information

Supply voltage
from 1.2 to 3.3 V
The voltage required to power the RAM module. All modules are designed for a specific voltage, so when choosing this item, make sure your motherboard supports the required voltage.

Chips

Manufacturer
Manufacturer of the microcircuits installed on the module. Often, memory module manufacturers use third-party chips to produce their products.

Quantity
from 1 to 184
The number of chips installed on one memory module. Microcircuits can be located on either side or on both sides of the board.

Package
Method of arrangement of chips on the memory module. Modules are available with single-sided and double-sided packaging. If the chips on the module are located on both sides, then the modules are thick, which prevents their installation in some systems.

This is a module whose function is to store data and provide it on demand to a device or program - essentially it is an intermediary between the processor and disk drives. RAM is a volatile device, i.e. can only work as long as power is supplied to it; if it is turned off, all data is lost. Let's take a closer look at the characteristics of this essential device, without which your PC, smartphone, laptop or tablet will be an ordinary pile of iron.

Types of RAM

RAM comes in several types, with radically different characteristics and architecture.

– synchronous dynamic random access memory. It used to be quite popular and was used in almost all computers, thanks to the presence of synchronization with the system generator, which, in turn, allowed the controller to very accurately determine the time when the data would be ready. As a result, the delay time for waiting cycles was significantly reduced due to the availability of data at each timer tick. Today it has been replaced by more modern types of memory.

is a dynamic synchronized memory, it is based on the principle of random access and double data exchange speed. Such a module has a number of positive characteristics relative to SDRAM, the most important of which is that 2 operations are carried out in 1 clock cycle of the system generator, that is, at a constant frequency, the peak bandwidth increases by 2 times.

- this is the next development, it works the same as DDR type RAM, distinctive feature This model consists of double data sampling per clock (4 bits instead of 2x). In addition, the second generation has become more energy efficient, heat generation has decreased, and frequencies have increased.

– a new generation of RAM, the most important distinguishing feature from DDR2 is increased frequencies and reduced energy consumption. The design of the keys has also been completely changed (special slots for precise fit into the slot).

There are modifications of DDR3, characterized by even lower energy consumption - DDR3L and LPDDR3 (the voltage in the first model is reduced to 1.35 V, and in the second to 1.2 V, while for simple DDR3 it is equal to 1.5 V).

DDR4 SDRAM - newest generation random access memory. It is characterized by a data exchange speed increased to 3.2 Gbit/s, a frequency increased to 4266 MHz and significantly improved stability.

RIMM(RDRAM, Rambus DRAM) - memory based on the same principles as DDR, but with an increased clock frequency level, which was achieved due to a smaller bus width. Also, when addressing a cell, the row and column numbers are transmitted simultaneously.

The cost of RIMM was much higher, and the performance was only slightly higher than DDR, as a result, RAM of this type did not last long on the market.

Choose the type of RAM not only based on the potential and characteristics of your motherboard, but also taking into account compatibility with other components of the system.

Options for physical arrangement of chips (packaging)

Memory chips installed on RAM modules are located either on one side (unilateral location) or on both sides (double-sided). IN latest version The modules are quite thick, which makes it impossible to install them on separate PCs.

Form factor is

A specially developed standard that describes the dimensions of the RAM module, the total number and location of contacts. There are several types of form factors:

SIMM (Single in Line Memory Module) - 30 or 72 double-sided contacts;

RIMM– proprietary form factor of RIMM modules (RDRAM). 184, 168 or 242 contacts;

DIMM(Dual in Line Memory Module) – 168, 184, 200 or 240 independent pads located on both sides of the module.

FB-DIMM(Fully Buffered DIMM) – exclusively server modules. Identical in form factor to DIMMs with 240 pins, but using only 96 due to the serial interface. Thanks to the AMB (Advanced Memory Buffer) chip present on each module, high-speed buffering and conversion of all signals, including addressing, are provided. Performance and scalability have also been significantly improved. Compatible only with similar fully buffered memory.

LRDIMM(Load Reduced Dual In-Line Memory Modules) – exclusively server modules. They are equipped with an iMB buffer (Isolation Memory Buffer), which reduces the load on the memory bus. Used to speed up the operation of large amounts of memory.

SODIMM(Small Outline Dual In-Line Memory Module) is a subtype of DIMM with smaller dimensions for installation in portable devices, mainly laptops. 144 and 200 contacts, in a rarer version - 72 and 168.

MicroDIMM(Micro Dual In-Line Memory Module) - an even smaller SODIMM. Typically have 60 contacts. Possible pin implementations are 144 SDRAM, 172 DDR and 214 DDR2.

Low Profile memory deserves special mention - modules created specifically for low server cases with a smaller height than standard ones.

Form factor is the main parameter for RAM compatibility with motherboard, since if it does not match, the memory module simply cannot be inserted into the slot.

What is SPD?

Each DIMM form factor strip has a small SPD (Serial Presence Detect) chip, which contains data on the parameters of physical chips. This information is critical for smooth operation and is read by the BIOS during the test phase to optimize RAM access parameters.

Memory module slots and their number

A 64-bit wide memory block (72 for ECC modules) formed by N physical chips. Each module can have from 1 to 4 ranks, and motherboards also have their own limitation on the number of ranks. Let us explain - if no more than 8 ranks can be installed on the motherboard, this means that the total number of RAM module ranks cannot exceed 8, for example, in this case - 8 single-rank or 4 double-rank. Regardless of whether there are still free slots left, if the rank limit is exhausted, it will be impossible to install additional modules.

Determining the rank for a specific RAM is quite simple. At Kingston, the number of ranks is determined by one of 3 letters in the center of the marking list: S is single-rank, D is double-rank, Q is four-rank. For example:

• KVR1333D3L S 4R9S/4GEC
• KVR1333D3L D 4R9S/8GEC
• KVR1333D3L Q 8R9S/8GEC

Other manufacturers indicate this parameter as, for example, 2Rx8, which means:

2R - two-rank module

x8 - data bus width on each chip

those. The 2Rx8 module without ECC has 16 physical chips (64x2/8).

Timings and latency

Any operation performed by a memory chip takes a certain number of system bus cycles. The number of clock cycles required for writing and reading data are timings.

Latency, in short - the delay in accessing memory pages, is also measured in the number of cycles and is recorded by 3 numerical parameters: CAS Latency, RAS to CAS Delay, RAS Precharge Time. Sometimes a fourth digit is added - “DRAM Cycle Time Tras/Trc”, which characterizes the overall performance of the entire memory chip.

CAS Latency or CAS(CL) – wait from the moment when the data was requested by the processor until it starts reading from RAM. One of the most important characteristics that determine the speed of RAM. A small CL indicates high RAM performance.

RAS to CAS Delay(tRCD) - the delay between the transmission of the RAS (Row Address Strobe) and CAS (Column Address Strobe) signals, necessary for the clear separation of these signals by the memory controller. Simply put, a data read request includes the row and column numbers of the memory page and these signals must be clear, otherwise multiple data errors will occur.

RAS Precharge Time(tRP) - determines the delay time between deactivation of the current data line and activation of a new one. In other words, the interval after which the controller can again send RAS and CAS signals.

Clock frequency, data transmission frequency (Data rate)

Data transmission frequency (otherwise known as data transmission rate) - the maximum possible number of data transmission cycles per second. Measured in gigatransfers (GT/s) or megatransfers (MT/s).

The clock frequency determines the maximum frequency of the system oscillator. We must remember that DDR stands for Double Data Rate, which means double the data exchange rate relative to the clock. So, for example, for the DDD2-800 module the clock frequency will be 400.

Throughput (peak data rate)

In a simplified version, it is calculated as the system bus frequency multiplied by the amount of data transferred per clock cycle.

The peak speed is the product of the frequency and bus width by the number of memory channels (B×R×K). The memory module is indicated as, for example, PC3200, which obviously means that the peak data transfer rate for this module is 3200 MB/s.

For optimal system operation, the total value of the PSPD of memory sticks should not exceed the PS of the processor bus, with the exception of dual-channel mode, when the sticks will occupy the bus in turn.

What is ECC (Error Correct Code) support?

ECC-enabled memory helps detect and correct spontaneous errors during data transfer. Physically, ECC is implemented as an additional 8-bit memory chip for every 8 main ones and is a significantly improved “parity control”. The essence of this technology is to track one bit arbitrarily changed during the process of writing/reading a 64-bit machine word and then correct it.

Buffered (registered) memory

It is characterized by the presence on the RAM module of special registers (buffers) that process control and addressing signals from the controller. Despite the additional latency introduced by the buffer, register memory is still widely used in professional systems due to the reduced load on the synchronization system and significantly increased reliability.

It must be remembered that buffered and unbuffered memory are incompatible and cannot work in the same device.

RAM- one of the most important components 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 on RAM, 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.

For the most modern processors fits . It is distinguished by doubled up to 3.2 Gbit/s maximum speed data transmission, maximum frequency increased to 4266 MHz 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 computer games and other applications to run more stable and faster. RAM prices are high clock frequency, needless to say, 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 gaming computer, powerful workstation or you plan to overclock all system components, then you should buy gaming memory, which differs from the standard one in higher frequency, higher voltage and, if possible, lower latencies. 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. To the most popular on this moment refers to the so-called . XMP support allows you to overclock DDR3 and DDR4 memory and thus achieve even more high performance and improve gaming features without complex changes in memory voltage and frequency.

ATTENTION! This article is not a call to action, but is for informational purposes only.

It is an equally important part of the computer. Despite the fact that this part is small in size, the speed of your computer largely depends on it. It has basic characteristics such as volume and frequency.

RAM capacity

The essence of the operation of RAM can be understood from its name: this is the memory that should work quickly. For example, you have HDD, on which some data is stored. You are running an application that receives data from hard drive necessary for work. If the computer constantly accesses the hard drive for the data it needs, it will take quite a lot of time - so it loads this data into RAM and can access it much faster, “here and now.” It follows that the larger the amount of RAM, the better.

As is the case with other computer components, the amount of RAM should be selected based on your goals. If you only work with undemanding office applications, then a large amount of RAM will simply be idle, and this is an unnecessary overpayment of money, while at the same time, users who work in more serious programs, for example, gamers, require more RAM. However, you should adhere to optimal option and purchase memory with a capacity of at least four gigabytes - this volume will be quite enough for comfortable work home computer, even for entertainment in games.

RAM frequency

The concept of frequency in RAM is responsible for its performance. That is, at what speed the computer can take and load the necessary data into this very memory. The principle “the more the better” also applies here.

There are several types of RAM. These are DDR, DDR2 and DDR3. Each of them differs in that it has a maximum frequency greater than that of the previous type. The optimal option would be a frequency from 1200 to 1600 MHz. If the budget is limited, then you should give preference to RAM with a lower frequency, but not less than 1200 MHz. This is due to the fact that the price of such memory will be lower, and the average user will not even notice the difference in performance.

Important points that are worth paying attention to

The most important thing is that the parts in our computer are not only fast, but also fully compatible. Therefore, you should definitely ensure that the type of memory, its size and frequency match the same parameters on the motherboard. If these parameters are incompatible, then it will either not work at all, or will not work as we would like. For example, if the maximum allowable amount of RAM on the motherboard is 8 gigabytes, and a RAM “bar” of 16 gigabytes is inserted, only half of the memory will be used, that is, extra money was overpaid.

So, there are regular and low-profile “bars”. Low profile have smaller sizes, which are suitable for small cases, but it will be difficult to insert a regular-sized “bar” into such a case. In order not to be mistaken, you can in any case take low-profile “bars”, since they are suitable for any case, and their performance is no different. Otherwise, be sure to ensure that the dimensions of the RAM “strips” match your case and motherboard.

Hello, dear readers of the blog site. Today I would like to talk about computer RAM. It (memory) is often called RAM - Random Access Memory, or RAM - which translated from bourgeois means “random access memory”, that is, memory not only for reading, but also for writing information.

A little higher, I mentioned the word “device”, although in reality it’s hard to call RAM a full-fledged device. Essentially, RAM consists of one or, more often than not, several rectangular strips. Many people, when they come to a computer store, are perplexed as to how they can pay 1000-2000 rubles for some crap! (depending on the size and type of memory, of course). Moreover, the bar is 2000 rubles. It’s far from the limit, believe me, there are even more expensive ones - just 5-6 times that.

The fact is that the computer's RAM is needed to store temporary information, i.e. until the computer turns off. Temporary information means OS ( operating system), All open source software and services and other little things. It turns out that the larger the amount of RAM, the more programs can be opened at the same time, the faster the OS itself will work, since there will be no need to constantly load OS files from . Of course there are many advantages, but the main ones are: speed and multitasking. In the situation with games there is nothing to talk about at all, everything is simple here, the more the better. But I think 16 GB will still be too much for games.

In 2006-2007, having even 1 GB of RAM “on board” was very cool. And although this volume was enough for most everyday tasks, it felt like the system was slowing down, and this was more noticeable in games. In fact, capacity is not the only important characteristic of RAM; there are two more: memory type and its frequency. I suggest we talk about this in more detail.

But first, let's take a look where is the RAM located.

As you can see, the RAM strips are attached to using special connectors; these connectors (slots) are only suitable for connecting computer RAM; no other devices can be connected there, as is the case with (where the connection interface is the PCI-E x16 slot, to which In addition to the video card, you can connect other devices).

As you can imagine, not all RAM is alike. I propose to look at how they may differ from each other. The first difference can be seen simply by looking at the memory. I'm talking about the height of the memory bar itself. Yes, just recently to everyone already familiar regular memory a “low-profile” version has been added, take a look:

This type of memory will be convenient for installation, especially if the space is system unit very limited, although initially this type memory was used for installation in server cases, due to the horizontal arrangement and low height of the latter.

So, as mentioned above, volume is not the most important parameter, which characterizes the computer's RAM. So what if the computer has 4 GB of RAM, but the type of memory is outdated, or the operating frequency is low.

What kind of guy is this, you may ask? I answer, There are two types of RAM, which differ from each other in the actual design of the bar itself and the speed of its operation (performance). Both of these memory types are called DDR2 and DDR3 respectively.

At the time of writing, DDR2 has already been practically ousted from the market by its descendant - DDR3, due to the fact that the energy consumption of DDR3 memory has decreased, according to various estimates, by 15%, compared to DDR2. DDR3 also has much greater bandwidth and operates stably at frequencies up to 1600 MHz. Please note that these two types of memory are not compatible with each other, and all because there are differences even in the memory connectors themselves.

The images above clearly show the reason for the incompatibility, namely, a small depression in the RAM strips, as well as a small notch in the memory slots on the motherboard. All this will prevent you from accidentally installing one type of memory into your computer instead of another, such is the “fool proof”. By the way, everything that was stated above in the text does not describe all the differences between DDR2 and DDR3 memory, but that was not the purpose of this post at all. I will only say that there will be other articles related to the topic “computer RAM”. I guess that's all I would like to talk about here. See you!