The Western Digital SN850X is a solid-state drive in the M.2 2280 form factor, launched on July 17th, 2024. It is only available in the 8 TB capacity listed on this page. With the rest of the system, the Western Digital SN850X interfaces using a PCI-Express 4.0 x4 connection. The SSD controller is the Black G2 (20-82-20035-B2) from WD, a DRAM cache chip is available. Western Digital has installed 162-layer TLC NAND flash on the SN850X, the flash chips are made by Kioxia. To improve write speeds, a pseudo-SLC cache is used, so bursts of incoming writes are processed more quickly. Thanks to support for the fast PCI-Express 4.0 interface, performance is excellent. The SN850X is rated for sequential read speeds of up to 7,200 MB/s and 6,600 MB/s write; random IOPS reach up to 1200K for reads and 1200K for writes.
At its launch, the SSD was priced at 849 USD. The warranty length is set to five years, which is an excellent warranty period. Western Digital guarantees an endurance rating of 4800 TBW, a typical value for consumer SSDs.