The Western Digital SN770M is a solid-state drive in the M.2 2230 form factor, launched in September 2023. It is available in capacities ranging from 500 GB to 2 TB. This page reports specifications for the 2 TB variant. With the rest of the system, the Western Digital SN770M interfaces using a PCI-Express 4.0 x4 connection. The SSD controller is the 20-82-10081-A1 Polaris MP16+ from WD, a DRAM cache is not available. Western Digital has installed 112-layer TLC NAND flash on the SN770M, the flash chips are made by Kioxia. To improve write speeds, a pseudo-SLC cache is used, so bursts of incoming writes are soaked up more quickly. The cache is sized at 638 GB, once it is full, writes complete at 500 MB/s. Copying data out of the SLC cache (folding) completes at 250 MB/s. Thanks to support for the fast PCI-Express 4.0 interface, performance is excellent. The SN770M is rated for sequential read speeds of up to 5,000 MB/s and 4,850 MB/s write; random IOPS reach up to 650K for reads and 800K for writes.
At its launch, the SSD was priced at 220 USD. The warranty length is set to five years, which is an excellent warranty period. Western Digital guarantees an endurance rating of 1200 TBW, a typical value for consumer SSDs.