nvm slotWhen you buy a new SSD, it uses either the SATA or NVMe interface to connect to your computer. Traditional SATA SSDs use the 2.5 form factor, as seen in the picture below.The ‘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.