DDR4 or DDR5
The motherboard decides this, not you. A board takes either DDR4 or DDR5, never both, and the sticks are shaped so the wrong type will not fit. Current AMD AM5 boards are DDR5 only; Intel boards exist in both versions, so check the board's memory type before buying.
How much
- 16 GB: enough for everyday use and many games, but newer games and having a browser open while playing can fill it.
- 32 GB: the comfortable choice for a gaming PC today, with room for streaming, browser tabs and future games.
- 64 GB or more: for video editing, large projects, virtual machines and other heavy work.
Two sticks, bought together
Most desktop boards run memory in dual channel, which needs two sticks in the slots the manual names. One stick on its own works, but more slowly. Buy a kit of two rather than two single sticks: the sticks in a kit are tested together and are far more likely to run at the rated speed.
Tip: Four sticks are harder for the board to run fast than two. If you want a lot of memory, two larger sticks are usually better than four smaller ones.
Speed and timings
Speed is given in megatransfers per second, such as 6000 MT/s (often written 6000 MHz). Timings are given as CL followed by a number, such as CL30. Higher speed is better and a lower CL number is better, and the two work together: a fast kit with loose timings can be no quicker in practice than a slightly slower kit with tight ones.
Faster memory helps some games and processors more than others. Past a sensible kit for the platform, the gains are small, and capacity and having two sticks matter more.
Getting the rated speed
Memory runs at a slow default speed until its profile is switched on in the BIOS. It is called XMP on Intel boards and EXPO or DOCP on many AMD boards. Our first boot guide shows where to find it.
Careful: Check the motherboard maker's memory support list, or at least that the board supports the speed you are buying. A board that does not support it will run the memory slower, or not start until the profile is turned off.