The Dell Precision 5750 Mobile Workstation Supports Single and Dual Drive Configurations. (Two M.2 NGFF (2280) or (2230) Solid State Drives) Note: Both M.2 slots support Generation 3.0 x4 PCIe NVMe Solid State Drives. When installing a M.2 PCIe NVMe Generation 4.0 x4 SSD in a M.2 PCIe NVMe Generation 3.0 x4 slot, the drive will run at PCIe Generation 3.0 x4 speeds. If installing a M.2 (2280) Drive in SSD slot 1, you will need the M.2 Drive thermal cooling bracket p/n HFD3T for installation. If installing a M.2 (2280) Drive in SSD slot 2, you will need the M.2 Drive thermal cooling bracket p/n JFF2T for installation. The M.2 (2230) Drive uses a adapter bracket p/n 07HMH to accommodate for the larger M.2 (2280) slots.