The Dell Alienware 17 R2 Laptop Supports up to 5 Drives. (One 2.5" Solid State Drive or Hard Drive and/or Four M.2 NGFF (2280) Solid State Drives) Note: If the 2.5" Drive was not installed from Dell, you will need the 2.5" Drive caddy p/n 4XYV6 and data cable p/n 00DPN for installation. (All 4 M.2 slots support SATA only Solid State Drives)