NVMe or SATA
There are two kinds of SSD in desktop PCs. NVMe drives are small M.2 sticks that plug straight into the motherboard and are much faster. SATA drives come as 2.5 inch drives with a data and a power cable, or as M.2 sticks, and are limited by the older SATA connection.
Careful: An M.2 slot may take NVMe drives, SATA drives or both. Check the motherboard's specifications for each slot before buying an M.2 SATA drive.
PCIe 3.0, 4.0 and 5.0
NVMe drives are sold by PCIe generation, and each one roughly doubles the top speed of the last. A drive works in an older slot, but only at that slot's speed. So a PCIe 5.0 drive in a PCIe 4.0 slot runs as a PCIe 4.0 drive.
For gaming and everyday use, the difference between a good PCIe 4.0 drive and a PCIe 5.0 one is hard to notice. The fastest drives help most with moving very large files.
Capacity
Choose the size before the speed. Games take a lot of space, and SSDs slow down and wear faster when nearly full, so leave some room free.
- 500 GB: tight for a gaming PC once Windows and a few games are installed.
- 1 TB: a sensible minimum for gaming.
- 2 TB or more: comfortable for a large game library, or add a second drive later.
What else differs
- DRAM cache: drives with their own memory cache keep their speed better under long, heavy use. DRAM-less drives are cheaper and fine for most people.
- Endurance: given as TBW (terabytes written). Ordinary use rarely comes near it, but a higher figure and a longer warranty are reassuring.
- Heatsink: fast drives get hot. Many motherboards have an M.2 heatsink; if yours does not, a drive with its own heatsink helps. Check it fits under the graphics card.
Compare the same capacity across shops on the product page, because one listing can cover several sizes. The PC builder helps you put the rest of the build together around it.