One M.2 NVMe, or one M.2 NVMm and one Optane. One M.2 2230 solid-state drive PCIe Gen3 x4 NVMe, up to 32 Gbps Up to 512 GB One M.2 2280 solid-state drive PCIe Gen3 x4 NVMe, up to 32 Gbps Up to 2 TB One M.2 2280 Intel Optane Memory H10 with Solid State Storage PCIe Gen3 x2 NVMe, up to 16 Gbps Up to 1 TB  
How many and what type of drives can you have in a 7706 17 inch 2n1?  
Inspiron 7706 - Hard Drives