M.2 drives can come in a few different sizes, but the main standard is M.2 2280. The “22” means that the M.2 drive is 22 millimeters wide, whereas the “80” means that the M.2 drive is 80 millimeters long.
M.2 NVMe SSD
“NVMe” stands for “Non-Volatile Memory Express”.
no longer using SATA bandwidth.
PCI Express SSD
SSDs that come in the form of PCI Express expansion cards and are ideal for motherboards that don’t support the M.2 form factor