The HP 256 G8 Notebook Supports Either Single Drive or Dual Drive Configurations Depending on the System Board Installed. (Single and Dual Drive Options with a Intel Core i3/i5/i7 Processor: One 2.5" Solid State Drive or Hard Drive and/or One M.2 NGFF (2280) Solid State Drive) or (Single Drive Options with a Intel Pentium or Celeron Nxxxx Processor: One 2.5" Solid State Drive or Hard Drive or One M.2 NGFF (2280) SATA Solid State Drive using a M.2 Drive Bracket) Note: When the M.2 (2280) Drive is installed in models with a Intel Pentium or Celeron Processor, the M.2 Drive occupies the 2.5" Drive bay by using a M.2 Drive bracket. If replacing the M.2 Drive for a 2.5" Drive in models with a Intel Pentium or Celeron Processor, or adding a 2.5" Drive to models with a Intel Core i3/i5/i7 Processor, you will need the 2.5" Drive caddy p/n Lxxxxx-001 and connector board p/n L52024-001 and cable p/n L52025-001 for installation. (The M.2 Drive board supports SATA only Solid State Drives and the M.2 slot on the Intel Core i3/i5/i7 system board supports SATA and PCIe NVMe Solid State Drives)