The Western Digital SN550 is a solid-state drive in the M.2 2280 form factor, launched on December 10th, 2019. It is available in capacities ranging from 250 GB to 2 TB. This page reports specifications for the 1 TB variant. With the rest of the system, the Western Digital SN550 interfaces using a PCI-Express 3.0 x4 connection. The SSD controller is the 20-82-01008-A1 Polaris MP16 from WD. Western Digital has installed 96-layer TLC NAND flash on the SN550, the flash chips are made by Toshiba. Please note that this SSD is sold in multiple variants with different NAND flash or controller, which could affect performance, the "Notes" section at the end of this page has more info. To improve write speeds, a pseudo-SLC cache is used, so bursts of incoming writes are processed more quickly. The SN550 is rated for sequential read speeds of up to 2,400 MB/s and 1,950 MB/s write; random IOPS reach up to 345K for reads and 385K for writes.
At its launch, the SSD was priced at 100 USD. The warranty length is set to five years, which is an excellent warranty period. Western Digital guarantees an endurance rating of 600 TBW, a typical value for consumer SSDs.