RAM: DDR4 or DDR5, XMP and dual-channel mode

For a gaming PC, always buy two identical memory modules (dual-channel mode) and enable the XMP or EXPO profile in the BIOS – otherwise the memory runs at the default, lower speed. The motherboard determines the memory type (DDR4 or DDR5). 16 GB is enough for esports and Full HD; 32 GB for demanding games and streaming.

Summary

• RAM is working memory for the processor and games – when there is too little of it or it is slow, games stutter.
• DDR5 is the standard on new platforms (AMD AM5, Intel Core Ultra), DDR4 on older ones (AM4, Intel up to 14th gen depending on the board).
• Without XMP/EXPO, memory runs at the base JEDEC speed. In our measurements, enabling XMP added up to several tens of per cent in FPS.
• Computers with integrated graphics (APUs) depend most on memory speed.

What the memory specs mean

Real latency in nanoseconds is calculated as CL × 2000 ÷ speed in MT/s. For example, DDR4-3600 CL16 has about 8.9 ns and DDR5-6000 CL30 about 10 ns – roughly the same, even though the CL number on DDR5 is double. A higher CL on DDR5 therefore does not automatically mean slower memory.

DDR4 or DDR5?

The motherboard decides the type – you cannot put DDR5 into a DDR4 slot or vice versa. The new AMD AM5 and Intel Core Ultra platforms support DDR5 only. For Intel 12th–14th gen there are boards for both DDR4 and DDR5. The AM4 platform with DDR4 is a cheaper route to a gaming PC or an upgrade, but no newer processors will come to it.

Memory prices rose sharply in 2026 due to demand from AI servers. So buy as much memory as you will actually use.

Why two modules and not one

Processors have a dual-channel memory controller. With two modules (e.g. 2 × 16 GB), memory works in two channels at once and bandwidth is roughly double that of a single module of the same capacity. In games this shows mainly in minimum FPS and smoothness. On boards with four slots, two modules go into the slots the board manufacturer marks as primary (usually A2 and B2).

XMP and EXPO: the speed you paid for

Without the profile enabled, memory runs according to the base JEDEC standard, often much slower than stated on the box. The XMP (Intel) or EXPO (AMD) profile sets the speed and timings at which the manufacturer tested the modules. It is enabled with a single switch in the BIOS.

When building gaming PCs at PC Praha, we measured the effect of XMP on two budget builds with 2 × DDR4-3600 memory:

These are older builds, but the principle still applies: integrated graphics have no memory of their own and use the computer's RAM. Fast dual-channel memory is therefore essential for PCs with integrated graphics.

If the computer does not boot or crashes after enabling the profile, try a lower speed or update the BIOS. You can verify memory stability with a test, as described in our article PC stress test. Further tuning options are covered in the article Overclocking your PC.

How much memory you need

• 8 GB: only for office work and web browsing.
• 16 GB (2 × 8 GB): esports and gaming in Full HD.
• 32 GB (2 × 16 GB): demanding games, streaming, 1440p and photo editing.
• 64 GB and more: video editing, 3D and work with local AI models.

How to match memory with the processor and graphics card is covered in our guide How to choose a gaming PC.

What next

• PC upgrades and service – we add memory and set up XMP/EXPO.
• Custom PC builds – a build with dual-channel memory.
• How to choose an SSD – another component that affects system speed.