The Lenovo ThinkPad X1 Carbon 3rd Generation Laptop Supports Single Drive Configuration Only. (One M.2 NGFF (2280) Solid State Drive) Note: This machine supports M.2 PCIe 3.0 x4 Solid State Drives, but the system board only runs at PCIe 3.0 x2 speeds. (The M.2 slot supports SATA and PCIe NVMe Solid State Drives)