The Lenovo ThinkPad P17 Gen 2 Laptop Supports up to 3 Drives. (Three M.2 NGFF (2280) Solid State Drives) Note: This machine comes with One M.2 (2280) Drive slot that supports Generation 4.0 x4 PCIe NVMe Drives and Two M.2 (2280) Drive slots that support Generation 3.0 x4 PCIe NVMe Drives. If installing a M.2 Generation 4.0 x4 PCIe NVMe Drive in a M.2 Generation 3.0 x4 PCIe NVMe slot, the drive will run at Generation 3.0 x4 speeds.