Which M.2 SSD drive?
Not all M.2 SSD drives are equal – there are two broad standards: those that connect using the SATA-III interface, which are slower but more compatible, and those that use the PCI-E module. These so-called NVMe SSDs can transfer data up to 32Gb/s (compared to 6Gb/s for SATA-III), but must be supported as bootable by your motherboard and Windows – of which only the later versions of Windows 10 support this feature, if you want to use them at their maximum speed. Don’t worry, though, as NVMe SSDs are backwards-compatible and will fall back to SATA-III mode if your motherboard doesn’t support this feature.
Note, though, that these slots share resources with other parts of the motherboard, so using them will disable at least one other port – typically SATA – on the board. Bear this in mind when choosing a motherboard with a limited number of SATA ports.
If in doubt, check the specifications of your target motherboard – most current-generation motherboards should support the NVMe feature (that’s ninth-generation Intel; and socket AM4 for AMD).
So-called NVMe M.2 SSD drives are significantly quicker than their SATA cousins.