The Dell XPS 17 9720 Laptop Supports Single and Dual Drive Configurations. (Two M.2 NGFF (2280) or (2230) Solid State Drives) Note: The M.2 (2280) and (2230) Drives each use a unique thermal heat shield brackets and cannot be interchanged. If replacing the M.2 (2230) Drive for a M.2 (2280) Drive in slot 1 (SSD1) or slot 2 (SSD2), the thermal heat shield bracket will need to be replaced for that slot unless it has already been provided by Dell. (Both M.2 slots support Generation 4.0 x4 and 3.0 x4 PCIe NVMe Solid State Drives)