M vs : What's the Difference?

2x slots M2_1 slot Supports up to PCIe x4 Supports 2242 2260 2280 storage devices M2_2 slot

Suits 1U form factor chassis at only 32mm total height; Support 1 x NVMe SSD utilizing PCIe x4 interface; Support 1 x SATA SSD

m24 slot wallet • SATA or PCIe x2 fits “B” key for SSD, WWAN, other non-storage devices • PCIe x4 up to 4GBs fitting “M” key modules for high performance SSD

m2 slot screw Socket 2 with Key B and Key C show less , ECN, October 22, 2021 The new BGA pinout content is based on the Socket 3 Key-M definitions