Bottom line: Western Digital has introduced a new option for Steam Deck or ROG Ally owners looking to swap out the storage solution in their handheld consoles. Capacities range from 500 GB to 2 TB, and pricing won't break the bank either.
The WD Black SN770M is an M.2 2230 NVMe solid-state drive, meaning it measures 22 mm wide and 30 mm long, and has its key in the M position. Until recently, it has been somewhat of a challenge to find retail M.2 2230 drives on the open market but that's starting to change as a handful of reputable brands including Corsair and Sabrent now offer solutions in this form factor.
Western Digital's SN770M is offered in 500 GB, 1 TB, and 2 TB capacities. Raw speed will vary slightly depending on which model you opt for. The fastest of the bunch – the 1 TB variety – is rated at up to 5,150 MB/s sequential reads / up to 4,900 MB/s sequential writes, and 740K random read IOPS / 800K random write IOPS.
Endurance also varies across models. The 500 GB version, for example, is rated for up to 300 TBW while the 2 TB model can withstand 1,200 TBW over its lifetime. All come backed by a five-year limited warranty.
The Steam Deck and Asus' ROG Ally ship with a 512 GB NVMe SSD as the largest storage option, and Valve specifically notes that its drive isn't intended for end-user replacement. Of course, a mild warning is not going to stop driven hardware enthusiasts seeking more space from moving forward with what amounts to a relatively straightforward replacement.
MSRP is set at $74.99 for the 500 GB model, $109.99 for the 1 TB version, and $219.99 for a 2 TB unit. The 500 GB and 1 TB model are available to purchase as of writing directly from Western Digital's store; the 2 TB model is currently out of stock but is available to pre-order from Best Buy for $239.99 with a ship date of September 22.