The Western Digital SN850X (w/ Heatsink) is a solid-state drive in the M.2 2280 form factor, launched on May 9th, 2022. It is available in capacities ranging from 1 TB to 4 TB. This page reports specifications for the 4 TB variant. With the rest of the system, the Western Digital SN850X (w/ Heatsink) interfaces using a PCI-Express 4.0 x4 connection. The SSD controller is the Black G2 (20-82-10035-B2) from WD, a DRAM cache chip is available. Western Digital has installed 112-layer TLC NAND flash on the SN850X (w/ Heatsink), the flash chips are made by Toshiba. To improve write speeds, a pseudo-SLC cache is used, so bursts of incoming writes are absorbed more quickly. Thanks to support for the fast PCI-Express 4.0 interface, performance is excellent. The SN850X (w/ Heatsink) is rated for sequential read speeds of up to 7,300 MB/s and 6,600 MB/s write; random IO reaches 1200K IOPS for read and 1000K for writes.
At its launch, the SSD was priced at 820 USD. The warranty length is set to five years, which is an excellent warranty period. Western Digital guarantees an endurance rating of 2400 TBW, a typical value for consumer SSDs.