Introduction

Western Digital (or simply WD) is the world’s largest manufacturer of storage solutions, mostly known for their wide range of hard disk offerings. With their acquisition of SanDisk in 2016, WD became one of the largest manufacturers for flash storage, too.

In this review, we’re checking out the WD Black SN770M, a remarkably compact M.2 NVMe drive adopting the 2230 form factor, with a mere 30 mm length. Its compact size makes it a perfect match for the Valve Steam Deck. Moreover, the SN770M is an option for expanding the storage on the ASUS ROG Ally game console and various Microsoft Surface Pro devices. Of course the drive will also fit into cases where an M.2 2242 PCIe drive has to be used.

In recent weeks we have reviewed several other M.2 2230 SSDs, which are all based on the same hardware design from Phison: a Phison E21 controller is paired with Micron 176-layer 3D QLC NAND flash. The WD Black SN770M is completely different. It uses only in-house components made by WD/SanDisk. The heart of the drive is the controller, which is the same 20-82-10081 that we’ve seen on the full-length WD SN770. The NAND flash is BiCS5 using 112-layer TLC technology. This is a major difference to the competing drives on the market, which are mostly QLC. As expected, a DRAM cache chip is absent due to space limitations, the SN770 (without M) is DRAM-less, too. The drive interfaces with the rest of the system through the PCI-Express 4.0 interface.

The WD Black SN770M is available in capacities of 500 GB ($80), 1 TB ($110) and 2 TB ($220). Endurance for these models is set to 300 TBW, 600 TBW and 1200 TBW, respectively. WD includes a five-year warranty with the SN770M SSD.