M.2 NVMe vs SATA SSD: what is the difference, and which should you buy?

It is confusing because it is two separate questions

People treat M.2, NVMe and SATA as three options to choose one of. They are really two questions on different layers.

• Shape — M.2 (a small stick that plugs into the board), 2.5" (a flat box on a cable), 3.5" (a spinning disk, on a cable)
• Connection — NVMe (fast, over PCIe) or SATA (slower, the older standard)

The two mix. Most M.2 drives are NVMe, but M.2 SATA drives exist — same shape, same slot, ten times the difference in speed. That is the trap that gets people.

Real figures from the drives in the catalogue

Top row to bottom row is a factor of 34. But the gap you actually feel is between the third row and the fourth, not between the first and the third.

The reason is that what a home machine does — booting Windows, opening programs, loading a game — is reading many small scattered files, not one long continuous one. The MB/s figure on the box measures the latter; the feeling comes from the former.

So what should you buy?

1. 1Windows goes on an SSD. NVMe or SATA, either is fine — but never a spinning disk. This is the single most noticeable upgrade of any on this list.
2. 2If you are buying an SSD, buy NVMe. The price gap between Western Digital Blue SN580 1TB and a SATA drive of similar capacity is smaller than you would think, and there is no cable to route.
3. 3Do not chase the top number. The difference between 4,150 and 7,450 MB/s is barely perceptible in ordinary use; the same money spent on capacity is worth more.
4. 4Spinning disks are still good value for storage. Seagate BarraCuda 2TB holds video or backups at a cost per gigabyte no SSD can match. Just do not put the operating system on it.

The arrangement that suits most machines is one NVMe drive for the system and games, plus one spinning disk for storage.

Check the board and the case can take it

Drives are not unlimited. There are ceilings in three places, and this site checks all three.

• M.2 slots on the board — an ITX board such as ASRock B650I Lightning WiFi has 2, while Gigabyte B650 EAGLE AX has 3.
• SATA ports on the board — every cabled drive uses one.
• Drive bays in the case — 3.5" and 2.5" bays are counted separately, and small cases have few.