The WD_BLACK SN7100 is a PCIe Gen4 x4 NVMe SSD (NVMe 1.4) in the M.2 2280 form factor, built on the WD/SanDisk Polaris 3 A101 controller and Kioxia 218-layer BiCS8 TLC NAND. Despite the high "7100" model number it is a PCIe Gen4 drive, not Gen5. It delivers sequential reads up to 7,250 MB/s and writes up to 6,900 MB/s with notably strong power efficiency, and was used in the Framework Laptop 13 Pro review unit tested by Tom's Hardware.
The WD_BLACK SN770M is a PCIe Gen4 x4 NVMe SSD in the compact M.2 2230 form factor — the size used by the Framework Laptop 16's secondary storage slot and the Framework Laptop 12. It is one of the few 2TB TLC 2230 drives available and is confirmed fitting and working in the FW16 alongside a 2280 primary.
The WD_BLACK SN850X is a PCIe Gen4 x4 NVMe SSD in the M.2 2280 form factor. It is one of Framework's officially compatibility-tested drives and a frequent community choice for the primary storage slot, with sequential reads up to 7,300 MB/s. Framework ships the related enterprise SN810 drive in pre-built Laptop 16 configurations.