The Addlink S91 is a solid-state drive in the M.2 2230 form factor, launched in April 2023. It is available in capacities ranging from 1 TB to 2 TB. This page reports specifications for the 1 TB variant. With the rest of the system, the Addlink S91 interfaces using a PCI-Express 4.0 x4 connection. The SSD controller is the PS5021-E21T from Phison, a DRAM cache is not available. Addlink has installed 176-layer QLC NAND flash on the S91, the flash chips are made by Micron. 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 handled more quickly. Thanks to support for the fast PCI-Express 4.0 interface, performance is excellent. The S91 is rated for sequential read speeds of up to 4,900 MB/s and 3,200 MB/s write; random IO reaches 570K IOPS for read and 750K for writes.
At its launch, the SSD was priced at 80 USD. The warranty length is set to five years, which is an excellent warranty period. Addlink guarantees an endurance rating of 250 TBW, a relatively low value compared to other SSDs.