The Lenovo ThinkPad Carbon X1 8th Gen Laptop Supports Single Drive Configuration Only. (One M.2 NGFF (2280) Solid State Drive) Note: M.2 Drives with PCIe NVMe Generation 4.0 x4 performance are downgraded to closer to PCIe NVMe Generation 3.0 x4 performance due to the system slot limitation. (The M.2 slot supports PCIe NVMe Solid State Drives)