The Lenovo ThinkBook 15 G4 ABA Laptop Supports Single and Dual Drive Configurations. (One M.2 NGFF (2280) or (2242) Solid State Drive and/or One M.2 NGFF (2242) Solid State Drive) Note: There are two M.2 slots on the system board, slot-1 (SSD1) supports M.2 2242 Drives only and slot-2 (SSD2) supports M.2 2280 and M.2 2242 Drives. If installing a M.2 2242 Drive in slot-2 (SSD2), the drive uses a adapter bracket p/n 5B40S22049 to accommodate for the larger M.2 2280 slot size. M.2 Drives with PCIe Generation 4.0 x4 performance are downgraded to closer to PCIe Generation 3.0 x4 performance due to AMD platform limitations.