The Alienware Area-51m R2 Laptop Comes in 2 Different Drive Options that Support up to 3 or 4 Drives. 3 Drive Configuration: (One 2.5" Solid State Drive or Hard Drive and/or Two M.2 NGFF (2280) or (2230) Solid State Drives) 4 Drive Configuration: (Two M.2 NGFF (2280) or (2230) Solid State Drives and/or Two M.2 NGFF (2280) Solid State Drives in a M.2 Dual Drive Interposer Board) Note: The M.2 Dual Drive Interposer board is Installed in the 2.5" Drive bay. If replacing the 2.5" Drive for the M.2 Dual Drive Interposer board, you will need the Interposer board p/n 0D3P25 and the bracket p/n 0R24Y6 and the thermal cover p/n 03JTF8 and the 30-Pin SSD-A cable p/n 05F1WR and the 50-Pin SSD-B cable p/n 02JH8P for installation. If replacing the M.2 Interposer board for a 2.5" Drive, you will need the 2.5" Drive caddy p/n 0J8J5W and cable p/n 02K51N for installation. (M.2 slot-1 (SSD1) and slot-2 (SSD2) support M.2 2280 or 2230 Solid State Drives - M.2 slot-3 (SSD3) and slot-4 (SSD4) on the Interposer board support M.2 2280 only Solid State Drives)