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, the speed of your computer largely depends on it. Has basic characteristics such as volume and frequency.
RAM size
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 a hard drive that stores some data. You are launching an application that needs data from the hard disk to work. If the computer is constantly accessing the hard disk for the data it needs, it will take quite a long time - therefore, it loads this data into RAM and can access it much faster, "here and now." It follows that the more RAM, the better.
As is the case with other computer components, the amount of RAM should be chosen based on the goals. If you work only with undemanding office applications, then a large amount of RAM will simply be idle, and this is an unnecessary overpayment of money, while users who work in more serious programs, for example, gamers, need more RAM. Nevertheless, you should adhere to the optimal option and purchase at least four gigabytes of memory - this amount will be quite enough for the comfortable work of a home computer, even for entertainment in games.
RAM frequency
Such a concept as the frequency in RAM is responsible for its performance. That is, at what speed the computer will be able to pick up 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 best 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 for such memory will be lower, and the average user will not even notice the difference in performance.
Important points to pay 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 make sure that the type of memory, its size and frequency coincide with the same parameters on the motherboard. If these parameters are incompatible, then it will either not work at all, or it will not work as we would like. For example, if the maximum allowable amount of RAM on the motherboard is 8 gigabytes, and a 16 gigabyte "strip" of RAM is inserted, only half of the memory will be used, that is, extra money was overpaid.
So, there are regular and low-profile "planks". Low-profile ones have smaller dimensions, which are suitable for small cases, but it will be difficult to insert a "bar" of a regular size into such a case. In order not to be mistaken, you can in any case take low-profile "trims", since they are suitable for any case, and their performance does not differ. Otherwise, be sure to make sure that the dimensions of the RAM "brackets" fit your case and motherboard.
Hello dear readers of the blog site. Today I would like to talk about the computer RAM. Its (memory) is often called RAM - Random Access Memory, or RAM - which in translation from the 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 fact the RAM cannot be called a full-fledged device. In fact, RAM is one or, most often, several rectangular strips. Many people come to a computer store and wonder how they can pay 1000-2000 rubles for some garbage! (depending on the amount and type of memory, of course). Moreover, the bar is 2,000 rubles. far from the limit, believe me, there is even more expensive - if so in 5-6.
The fact is that the computer's RAM is needed to store temporary information, i.e. until the computer is turned off. Temporary information means the OS (operating system), all open programs and services, and even all sorts of garbage on little things. It turns out that the larger the amount of RAM, the more programs can be opened simultaneously, 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 still - performance and multitasking... In a situation with games, there is nothing to talk about at all, everything is simple, the more the better. But I think 16 GB for games will still be a bit too much.
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 in games it was more noticeable. In fact, volume is not the only important characteristic of RAM, there are two more: the type of memory and its frequency. I propose to talk about this in more detail.
But first, let's see with you, where is the RAM located.
As you can see, the RAM strips are attached to using special connectors, these connectors (slots) are suitable only for connecting the computer's RAM, no other devices can be connected there, as in the case of (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 RAMs are alike. I propose to see how they can differ from each other. The first difference can be seen simply by looking at memory. I'm talking about the height of the memory bar itself. Yes, quite recently, a "low-profile" version of it was added to the already familiar ordinary memory, take a look:
This type of memory will be convenient for installation, first of all, if the space in the system unit is very limited, although initially this type of memory was used for installation in server cases, due to the horizontal arrangement and the low height of the latter.
So, as mentioned above, volume is not the most important parameter that characterizes the computer's RAM. So what if the computer has a 4 GB RAM bar, but the type of this 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 types of memory are called DDR2 and DDR3 respectively.
At the time of this writing, DDR2 has already been practically ousted from the market by its descendant - DDR3, due to the fact that the power consumption of DDR3 memory has decreased, according to various estimates, by 15%, in comparison with DDR2. And DDR3 also has much higher 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 this is because there are differences even in the memory slots themselves.
The images above clearly show the reason for the incompatibility, namely, a small indentation in the RAM strips, as well as a small notch in the memory slots on the motherboard. All this will not allow you to accidentally put one type of memory in a computer instead of another, such is the "fool's protection". By the way, all 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 can only say that there will be other articles related to the topic "computer memory". Perhaps this is all that I would like to talk about here. See you!
Random access memory is 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 volume of 1 to 32 GB, single strips, as well as KIT memory modules of 2 and 4 strips in a set with the same characteristics, selected for operation in pairs (dual-channel mode). The use of dual channel mode results in a significant increase in throughput, and, therefore, in an increase in the speed of applications. For compact systems, low-profile memory modules are provided that differ from the standard ones in height, but not in performance. While for outdated platforms there are regular and server RAM modules of the Registered DDR, DDR2, Registered DDR2 and DDR2 FB-DIMM standards. Affordable prices for these standards make the choice an obvious choice when looking for a replacement for faulty memory or expanding the available total memory on the system.
Today, the most common type of memory for Intel and AMD-based desktop PCs is DDR3 RAM. However, undervoltage (LV DDR3) is not supported by all motherboards and processors.
Suitable for the most modern processors. It is distinguished by the maximum data transfer rate doubled to 3.2 Gbps, the maximum frequency increased to 4266 MHz and the unsurpassed stability of work. The increased pin count makes DDR4 modules incompatible with older slots.
The higher the clock frequency, the more operations are performed per unit of time, which allows more stable and faster operation of computer games and other applications. The prices for high clock speed RAM are, of course, higher. But before you buy memory, pay attention to the maximum frequency 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 building a gaming computer, a powerful workstation, or are planning to overclock all system components, then you should buy a game memory that differs from the standard higher frequency, higher voltage and, if possible, lower latencies. The prices for gaming memory are not the lowest, but in this case the system performance will be higher than when using standard memory strips. Illuminated will become a decoration of any gaming PC. White or multicolor backlighting does not affect performance indicators, but it looks very stylish and relevant for a PC of this class.
Fast memory modules are distinguished by the presence of profiles that extend the capabilities of the SPD. The most popular at the moment is the so-called. XMP support enables DDR3 and DDR4 memory to be overclocked for even higher performance and improved gaming features without complex memory voltage or frequency changes.
This is a module whose function is to store data and provide it on demand to a device or program - in fact, it is an intermediary between the processor and disk drives. RAM is a volatile device, i.e. it can only work while it is powered, if turned off, all data is lost. Let's take a closer look at the characteristics of this most important device, without which your PC, smartphone, laptop or tablet will be an ordinary pile of iron.
RAM types
There are several types of RAM, radically different in characteristics and architecture.
- synchronous dynamic memory with random access. 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 latency time for wait cycles has been significantly reduced due to the availability of data at each timer clock cycle. Today it has been supplanted by more modern types of memory.
Is a dynamic synchronized memory based on the principle of random access and double data exchange rate. Such a module has a number of positive characteristics relative to SDRAM, the most important of which is that 2 operations are performed per 1 clock cycle of the system oscillator, that is, at a constant frequency, the bandwidth at its peak doubles.
- this is the next development, it works the same as that of DDR-type RAM, a distinctive feature of this model is the doubled data sampling per clock (4 bits instead of 2x). In addition, the second generation has become more energy efficient, heat dissipation has decreased, and frequencies have increased.
- a new generation of RAM, the most important distinguishing feature from DDR2 is higher frequencies and reduced power consumption. Also, the design of the keys has been completely changed (special slots for precise entry into the slot).
There are DDR3 modifications that differ in even lower power consumption - DDR3L and LPDDR3 (the voltage of the first model is reduced to 1.35 V, and in the second to 1.2 V, while in simple DDR3 it is 1.5 V).
DDR4 SDRAM- the latest generation of random access memory. It is characterized by increased data rate up to 3.2 Gbit / s, increased frequency to 4266 MHz and significantly improved stability.
RIMM(RDRAM, Rambus DRAM) - memory based on the same principles as DDR, but with a higher clock frequency, which was achieved due to a lower 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, this type of RAM 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 considering compatibility with other components of the system.
Variants of physical arrangement of chips (packaging)
Memory chips installed on RAM modules are located either on one side (one-sided location) or on two (double-sided). In the latter case, the modules are thick enough that they cannot be installed 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, located on both sides of the module, contact pads.
FB-DIMM(Fully Buffered DIMMs) - Server modules only. Identical in form factor DIMMs with 240 pins, but use 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, is provided. Performance and scalability are also significantly improved. Compatible only with equivalent fully buffered memory.
LRDIMM(Load Reduced Dual In-Line Memory Modules) - exclusively server modules. Equipped with an iMB (Isolation Memory Buffer) buffer, which reduces the load on the memory bus. They are used to speed up the work of large amounts of memory.
SODIMM(Small Outline Dual In-Line Memory Module) - 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) - even smaller SODIMM. They usually have 60 contacts. Possible pin implementations are 144 SDRAM, 172 DDR and 214 DDR2.
Special mention should be made of Low Profile memory - modules designed specifically for low server chassis with a lower height compared to standard ones.
The form factor is the main parameter of RAM compatibility with the motherboard, since if it does not match, the memory module simply cannot be inserted into the slot.
What is SPD?
Each DIMM bar has a small SPD (Serial Presence Detect) chip, which contains data on the parameters of physical chips. This information is critical to smooth operation and is read by the BIOS during the test phase to optimize the RAM access parameters.
Memory module ranks and their number
64-bit 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 limit 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 ranks of RAM modules cannot exceed 8, for example, in this case - 8 single-rank or 4 dual-rank. Regardless of whether there are still free slots - if the limit of ranks is exhausted, additional modules cannot be installed.
Determining the rank for a particular RAM is quite simple. At Kingston, the number of ranks is determined by one of 3 letters in the center of the bulletin list: S for peer-to-peer, D for druhrang, Q for four-rank. For instance:
- 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 - the width of the data bus on each chip
those. a 2Rx8 module without ECC has 16 physical chips (64x2 / 8).
Timings and latency
Any operation by a memory chip takes a certain number of system bus cycles. The number of clock cycles required for writing and reading data is the timings.
Latency, in short, the latency of 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 speed of the entire memory chip.
CAS Latency or CAS(CL) - waiting from the moment when the data was requested by the processor and until the start of reading them from RAM. One of the most important characteristics that determine the speed of RAM. A small CL indicates a high speed of RAM.
RAS to CAS Delay(tRCD) - the delay between the transmission of the RAS (Row Address Strobe) and CAS (Column Address Strobe) signals, which is necessary for the clear separation of these signals by the memory controller. Simply put - the request to read data includes the row and column numbers of the memory page and these signals must be distinct, otherwise multiple data errors will occur.
RAS Precharge Time(tRP) - defines the delay time between the deactivation of the current data line and the activation of a new one. In other words, the interval after which the controller can again send RAS and CAS signals.
Clock frequency, data rate
Data transfer rate (Otherwise - data transfer rate) - the maximum possible number of data transfer cycles per second. Measured in gigatransfers (GT / s) or megatransfers (MT / s).
The clock frequency determines the maximum frequency of the system oscillator. It must be remembered that DDR stands for Double Data Rate, which means twice the data exchange rate relative to the clock. So, for example, for the DDD2-800 module, the clock frequency will be 400.
Bandwidth (peak data rate)
In a simplified form, it is calculated as the system bus frequency multiplied by the amount of data transmitted per clock cycle.
The peak speed is the product of the frequency and width of the bus by the number of memory channels (H × 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 operation of the system, the total value of the PSPD of the memory strips should not exceed the PS of the processor bus, with the exception of the two-channel mode, when the strips will occupy the bus in turn.
What is ECC (Error Correct Code) support
ECC-enabled memory allows you to find and correct spontaneous errors during data transfer. Physically, ECC is implemented in the form of an additional 8-bit memory chip for every 8 main ones and is a significantly improved "parity" check. The essence of this technology is to track one bit randomly changed in the process of writing / reading a 64-bit machine word with its subsequent correction.
Buffered (register) memory
It is characterized by the presence of special registers (buffers) on the RAM module that process control and address signals from the controller. Despite the additional clock latency due to the buffer, register memory is nevertheless widely used in professional systems due to the reduced load on the synchronization system and significantly increased reliability.
Remember that buffered and unbuffered memory are incompatible and cannot work in the same device.
A type of random access memory that defines the main characteristics of the memory and the internal structure. Today there are five main types of random access memory: SDRAM, DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM, RIMM.
SDRAM is a synchronous dynamic memory that has random access. Advantages compared to the memory of older generations: synchronization with the system generator, this allows the memory controller to know the specific time of data availability, with the help of this innovation, the time delays during the waiting cycles are reduced due to the fact that the data is free for available during each cycle timer. Previously, SDRAM was actively used in computers, but now it is almost completely replaced by DDR and DDR2.
DDR SDRAM is a random access synchronous dynamic memory with twice the data transfer rate. Advantages of DDR SDRAM over SDRAM: during one cycle of the system generator, it is possible to perform two operations with information, which doubles the peak throughput when operating at the same frequency.
DDR2 SDRAM is the next generation of memory after DDR. The principle of operation is similar to that used in DDR. Difference: there is a possibility of sampling 4 data bits per cycle (for DDR, 2-bit sampling is performed), increased operating frequency, reduced power consumption of memory modules, reduced heat dissipation.
DDR3 SDRAM is the next generation of DDR2 SDRAM and uses the same "frequency doubling" technology. The main difference from DDR2: the ability to work at a higher frequency. DDR3 modules have 240 contact pads available, however, they are incompatible with the old slots, since different alignment slots ("keys") are used.
RIMM (Rambus DRAM, RDRAM) is a Synchronous Dynamic Memory (SDM) developed by Rambus. The main differences from DDR memory are: increasing the clock frequency by decreasing the bus width, simultaneously transmitting the column and cell row numbers when accessing the memory. RDRAM is much more expensive than DDR, and with similar performance, this led to the fact that this type of memory 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 on 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 - 72 or 30 contacts are often located on memory modules of this standard, each of these contacts is equipped with an outlet on both sides of the memory card.
DIMMs are memory modules of the DIMM standard, usually they have 240, 200, 184 or 168 independent pads, the pads are located on both sides of the memory card.
DDR2 FB-DIMM - memory modules of this standard are used in servers. They are mechanically similar to 240-pin DIMMs, but completely incompatible with regular unbuffered Registered DDR2 DIMMs and DDR2 DIMMs.
SODIMM is a compact variant of DIMM commonly found in Tablet PCs and laptops. Most often it has 72, 144, 168, 200 contacts.
MicroDIMM is one of the DIMM options for subnotebooks and notebooks. It has less dimensions than SODIMM, it is characterized by the presence of 60 contact pads.
RIMM is a standard for RIMM memory modules (RDRAM), characterized by the presence of 184, 168 or 242 pins.
The standard of the RAM module and the standard that the motherboard supports must be the same.
Volume of one module
from 0.03125 to 128 GB
The amount of memory that one module has. The total system memory can be calculated by adding the memory sizes of all installed modules. For comfortable work in office programs and the Internet, 512 MB is enough. For normal work with office applications, as well as with graphic editors, 1 GB (1024 MB) of RAM is enough. Working in complex graphics programs and playing computer games will allow 2 GB (2048 MB) of system memory.
Number of modules
from 1 to 16
The number of memory modules sold in the kit. There are not only single strips on sale, but also kits, the kit may 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 two-channel mode allows you to achieve a tangible 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, having the same characteristics, does not mean at all that they will be able to work in two-channel mode. For this reason, if the motherboard of your computer is capable of supporting dual-channel memory operation, then you should pay attention to kits consisting of several modules, if, of course, high speed of graphics and gaming applications is important to you.
Number of contacts
from 144 to 288
The number of contact pads located on the memory module. The number of pins on the module must match the number of pins in the RAM slot located on the motherboard. It should be remembered that in addition to the same number of contacts, "keys" must also match ("keys" are called cutouts on the module, they exclude 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 ranks. Server motherboards released today are characterized by the presence of a limit on the total number of memory ranks, for example, if a maximum of eight ranks can be installed and four dual-rank modules are already installed, then it will no longer be possible to install additional modules in free slots, because setting them will cause the limit to be exceeded. That is why single-rank modules are more expensive than two- and four-rank modules.
Clock frequency
66 to 4800 MHz
The lowest frequency of the system generator, according to which the processes of receiving and transmitting information are synchronized. For DDR, DDR2 and DDR3 memory, double the clock frequency is indicated (two operations with data are performed in one clock cycle). The higher the clock frequency, the more operations can be performed per unit of time, this allows computer games and other applications to run more stable and faster. With all other characteristics being the same, memory with a higher frequency is more expensive.
Bandwidth
from 1600 to 38400 Mb / s
The bandwidth of a memory module is the amount of information received or transmitted per second. This parameter is directly dependent on the memory clock frequency. The bandwidth of the memory module is calculated by multiplying the bus width by the clock frequency. The higher the bandwidth, the higher the memory speed, the higher the price of the module (if the other characteristics are the same).
ECC support
Support for ECC (Error Checking and Correction) algorithm, which makes it possible to both detect and correct errors that accidentally occurred during data transmission (no more than one bit in a byte). Almost all server boards, as well as some workstation motherboards, can support Error Checking and Correction. ECC memory modules are more expensive than non-ECC memory modules.
Buffered (Registered)
The presence of a buffer (special registers) on the memory module, special registers can quickly save the received 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 the appearance of an additional delay equal to one cycle when performing operations, thus, higher reliability is due to a slight decrease in performance. Memory modules equipped with registers are characterized by high cost, they are mainly used in servers. Keep in mind that unbuffered and buffered memory are incompatible, which means that they cannot be used simultaneously on the same system.
Low Profile
A memory module that has a smaller height (compared to the standard size). This size makes it possible to install it in low server chassis.
Radiator
The presence of special metal plates fixed on memory microcircuits, these plates are designed to improve heat transfer. Heat sinks are usually installed on memory modules that operate at high frequencies.
XMP support
XMP (eXtreme Memory Profiles) - a profile containing information about the extended and non-standard capabilities of the RAM module. By means of the BIOS of the computer at the initial period of loading, it switches to the overclocking mode, without manually adjusting all the delays.
Timings
from 2 to 22
CAS Latency, CAS - the number of clock cycles from the time the data is requested until it is read from the memory module. CAS Latency, CAS is the most important characteristic of a memory module, it will determine the speed of the memory. As the CL number decreases, the memory work faster.
tRCD
from 2 to 26
RAS to CAS Delay is the delay between 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, the recharge of the RAS signal (re-issue time), i.e. the time after which the memory controller can again issue the line address initialization signal.
tRAS
from 5 to 52
Activate to Precharge Delay is the smallest number of cycles between RAS (activation command) and Precharge (recharge command) or closure of the same memory bank.
Additional Information
Supply voltage
1.2 to 3.3 V
Voltage required to power the RAM module. All modules are designed for a specific voltage, therefore, when choosing this element, make sure that your motherboard supports the required voltage.
Chips
Manufacturer
The manufacturer of the microcircuits installed on the module. Often, manufacturers of memory modules use third-party chips for the release of their products.
Quantity
from 1 to 184
The number of chips installed on one memory module. Microcircuits can be located on either side and on both sides of the board.
Package
The way the chips are located on the memory module. Modules are available in single-sided and double-sided packaging. If the microcircuits on the module are located on both sides, then the modules are thick, which prevents them from being installed in some systems.
