The Dell G17 7790 Gaming Laptop Supports Either 1 or 2 Drives Depending on the Battery Installed. (One 2.5" Solid State Drive or Hard Drive with the Smaller 4-cell 60Whr Battery Installed and/or One M.2 NGFF (2280) or (2230) Solid State Drive) or (One M.2 NGFF (2280) or (2230) Solid State Drive with the Larger 6-cell 90Whr Battery Installed) Note: Models that have the larger 6-cell 90Whr battery installed do not Support 2.5" Drives due to the larger battery occupying the 2.5" Drive bay. If the 2.5" Drive was not installed from Dell in models with the smaller 60Whr battery installed, you will need the 2.5" Drive caddy p/n MM1KT and cable p/n J86N0 for installation. The M.2 slot supports M.2 (2280) and (2230) Drives by moving the drive mounting bracket to accommodate the form factor. (The M.2 slot supports PCIe NVMe Solid State Drives)