Quick Answer
An NVMe SSD is significantly faster than a SATA SSD. For your operating system, games, and frequently used apps, buy NVMe. SATA SSDs are best reserved for cheap bulk storage or older systems without an M.2 slot.
The Interface Difference
SATA SSDs use the older SATA III interface, which caps out around 550 MB/s. NVMe SSDs use the PCIe bus directly, with Gen 3, Gen 4, and Gen 5 drives reaching roughly 3,500, 7,000, and 14,000 MB/s respectively.
Does the Speed Matter in Real Life?
For booting Windows, launching games, and transferring large files, NVMe is noticeably snappier. For everyday tasks the gap between a good SATA SSD and NVMe is smaller than the raw numbers suggest, but NVMe is now the standard.
M.2 Is a Shape, Not a Speed
M.2 describes the small stick shape and slot, not the protocol. An M.2 slot can carry NVMe (PCIe), SATA, or both, depending on the motherboard. Check your motherboard manual: some M.2 slots are PCIe-only, some accept M.2 SATA drives, and on some boards using a particular M.2 slot disables one or two SATA ports. A 2.5-inch SATA SSD needs a SATA data cable and a power cable from the PSU; an M.2 drive needs neither.
PCIe Generations Work Together
NVMe drives and slots are backward compatible. A PCIe Gen 4 drive works in a Gen 3 slot, just at Gen 3 speed, and a Gen 3 drive works in a Gen 4 or Gen 5 slot at its own speed. Gen 5 drives only reach their full speed in a Gen 5 M.2 slot, which recent AM5 and Intel boards provide on at least one slot (check which one).
Cache, Flash Type and Heat
Two drives with the same headline speed can behave differently. Drives with their own DRAM cache, or DRAM-less drives that use HMB (a slice of system memory), stay responsive for everyday use. TLC flash keeps its speed better during long copies than QLC flash, which slows sharply once its fast SLC cache fills. Fast Gen 4 and especially Gen 5 drives get hot and slow down when they overheat, so use the motherboard's M.2 heatsink if it has one.
For a PS5
The PS5 expansion slot takes an M.2 NVMe PCIe Gen 4 drive. Sony recommends a sequential read speed of 5,500 MB/s or faster and a heatsink (or a drive with one built in). SATA drives do not fit the PS5 M.2 slot.
Which Should You Buy?
If your motherboard has an M.2 slot, buy an NVMe drive — the price difference is small. Reserve SATA SSDs for adding extra capacity or for older boards. Compare current SSD prices on SaudiPCPrice.