nvm slotThe ‘Key M’ or ‘M key’ slot is specifically for PCI-E SSDs aka NVME SSDs which are currently the fastest SSD type that one can buy. The ‘Key B’ slot is for M.2 SATA SSDs.NVMe drives are exclusively compatible with the M.2 slot on a motherboard. It is essential to verify if your motherboard has any M.2 slots.