Description
The Samsung PM981a is a solid-state drive in the M.2 2280 form factor, launched in 2020. It is available in capacities ranging from 256 GB to 1 TB. This page reports specifications for the 256 GB variant. With the rest of the system, the Samsung PM981a interfaces using a PCI-Express 3.0 x4 connection. The SSD controller is the Phoenix (S4LR020) from Samsung, a DRAM cache chip is available. Samsung has installed 92-layer TLC NAND flash on the PM981a, the flash chips are made by Samsung. 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 absorbed more quickly. The cache is sized at 12 GB, once it is full, writes complete at 500 MB/s. The PM981a is rated for sequential read speeds of up to 3,500 MB/s and 2,200 MB/s write; random IO reaches 240K IOPS for read and 480K for writes.
