How to choose RAM for a computer or laptop

1. Select Form Factor

Desktop computers and laptops use different types of RAM. Models differ in size and connector for connection to motherboard. Full-sized PCs install DIMM (Dual In-Line Memory Module) modules, and laptops - SO-DIMM (Small Outline Dual In-Line Memory Module), that is, more compact options.

The standard DIMM length is 133.35mm, while the SO‑DIMM is 67.6mm. The DIMM has 288 pins for communication with the motherboard, while the SO-DIMM has 260 of them.

When buying, pay attention to the type of memory, as well as its cooling system. Inexpensive modules that are not designed for overclocking, usually supplied without heatsinks. More expensive options for gaming computers or workstations are equipped with metal overlays that allow the RAM to cool faster after a heavy load.

But keep in mind that modules with large heatsinks are larger than standard memory sticks. Therefore, you need to make sure that there will be enough space for them on the motherboard along with the rest of the devices. Manufacturers indicate the dimensions in the specifications.

What RAM to buy

• RAM G.SKILL Ripjaws V 64 GB DIMM, from 15 240 rubles →
• RAM Kingston FURY Beast 32 GB DIMM, from 8 460 rubles →
• RAM Kingston ValueRAM 32 GB SO‑DIMM, from 7,199 rubles →
• RAM Patriot Memory SL 16 GB SO‑DIMM, from 2,989 rubles →

2. Decide on the type of memory

Most modern computers use DDR SDRAM (Double Data Rate Synchronous Dynamic Random Access Memory). Five versions have been released so far: DDR, DDR2, DDR3, DDR4 and DDR5.

The most common option for PCs at the moment is DDR4, but there is an active transition to the more powerful DDR5. It is important to note that DDR5 is not compatible with previous generation motherboards and processors, and DDR4 will not work in the latest systems.

If you are planning to upgrade your computer in the next couple of years, then you can choose DDR4 now. But if a performance margin is important to you for the future, then it is better to install DDR5 right away.

It is also worth paying attention to the memory channel. It is better to use two RAM modules - with one module the central processor will work in single-channel mode, and this will reduce the overall performance of the computer.

In addition, it is important to choose a rank - the number of arrays of memory chips installed on one module. RAMs are one-, two- and four-ranked. Single-rank modules usually include 4 or 8 chips per stick, dual-rank modules have 16 chips, and quad-rank modules have 32 chips.

The rank is usually indicated by one letter in the model name: S (single) - single-rank, D (double) - two-rank, Q (quad) - four-rank. The first modules are cheaper and work noticeably faster when overclocked. The latter are initially more productive, so the increase is not felt so much. The latter are the fastest and most often used in server systems, but the least stable with additional overclocking.

What RAM to buy

• RAM Corsair Dominator Platinum RGB 32 GB DDR5, from 34,550 rubles →
• RAM Corsair Vengeance RGB 32 GB DDR5, from 17,487 rubles →
• RAM Kingston FURY Beast 16 GB DDR5, from 8,968 rubles →
• RAM Patriot Memory Viper Steel 16 GB DDR4, from 8,084 rubles →

3. Check clock speed and timings

The clock speed of a RAM module in MHz determines how fast it can process data. Although performance is also affected by the capacity, timings and motherboard slots in which the RAM strips are installed.

By CAS timings (Column Access Strobe) we understand the delay in cycles that it takes to receive content from memory cells. Timings are recorded in the form of four parameters: 16–17–18–35. Each of them indicates the minimum performance for data access and transfer, as well as the overall performance of the module.

The higher the frequency of the RAM and the lower its timings, the better. For example, if you choose from two memory kits, one at 3200 MHz with timings of 14-14-14-34 and the second at 3600 MHz with the same performance, then you should take the second one.

Timings are also important during overclocking: a significant increase in the memory frequency requires tuning their parameters. If this is not taken into account, the system may become unstable.

Xtreme Memory Profile (XMP) is a profile of settings that are stored in RAM. It represents certain frequencies and timings at which the module must operate. Keep in mind that modules with XMP support will not immediately work at the advertised frequencies. These settings must first be enabled in BIOS.

If you do not want to go deep into overclocking, choose memory with XMP profiles. With their help, you can easily and simply increase the clock frequency of the RAM. However, if you want to get the maximum, you will have to study the user manual in more detail and set everything up manually.

There is also a Qualified Vendors List (QVL) - this is a list of RAM modules tested on a specific motherboard, indicating all frequencies, voltages and timings. If the memory is in the QVL of the motherboard you are interested in, then you can buy it. QVL for the desired model can be found on the official website of the manufacturer.

Overpaying for expensive memory kits is worth it only if you know for sure that you will use the RAM to its full potential and configure it in detail. The performance difference between them and more affordable models may not be very noticeable.

In addition, fast memory will be useless if another component of the system limits the speed of operation. It should be combined with the same powerful components.

4. Learn about available motherboard slots and CPU limits

Motherboards of compact formats often have two slots for installing memory modules. Large ATX models usually have four slots, while high-end models for powerful computers have eight or more.

The motherboard must be compatible in frequency with the RAM modules. Models with a higher frequency can be installed, but they will work more slowly. When buying, also pay attention to the maximum amount of supported memory.

At the same time, central processors also have a limit on the maximum amount of memory. But this limit won't be a problem for modern CPUs, which typically accept up to 128 GB.

A processor designed for two memory channels will not work in four-channel mode, even if you install four modules. In this case, a CPU compatible with the desired number of channels is required. Such processors belong to the premium price category or to server systems.

The number of memory channels in the processor can be checked in the manufacturer's official specifications.

6. Select the size and number of memory modules

Volume is one of the most important factors. At the moment, 16 GB is the minimum required when building a new computer. In a gaming PC, 32 GB is better. But 8 GB is already too little. Upgrading to 128 GB is worth it if you are going to use resource-intensive programs (for example, for video editing) or just want to prepare the device for the future.

The number of modules is limited by the design features of the motherboard. If you have four slots, and all of them are occupied by 8 GB RAM modules, then you will have to get rid of the old brackets to upgrade. Therefore, it is initially more profitable to purchase larger memory modules.

Please note that modules do not have to be identical in order to work together. But the frequency and timings will correspond to the operating parameters of the slower one.

What RAM to buy

• G.SKILL Trident Z Neo 64 GB RAM (32 GB x 2), from 17,386 rubles →
• RAM Kingston FURY Beast RGB 64 GB (32 GB x 2 pcs.), from 19,111 rubles →
• RAM Patriot Memory Viper Elite II 64 GB (32 GB x 2), from 14,314 rubles →
• RAM Crucial 32 GB, from 7,364 rubles →