As first spotted by German site HardwareLuxx, there’s no indication as to why Valve made this change, and it doesn’t look like anyone with an outstanding Steam Deck order will know which SSD bandwidth they’ll get in advance. However, Valve’s added note explains that “In our testing, we did not see any impact to gaming performance between x2 and x4.” It wouldn’t be surprising to see a negligible difference in game loading speeds, as most games simply aren’t built to take full advantage of PCIe 3.0 x 4’s bandwidth. It’s not like Gen 3.0 x2 SSDs are sluggish, either – they’re still speedy NVMe drives with more bandwidth to play with than any SATA-based SSD. Still, the Steam Deck is usable for more than just games, and spec crapshoots are never fun. Remember how the Nintendo 3DS could come with either IPS or TN screens? If you have ordered a Steam Deck and it turns up with the lower-spec SSD – and you find you can’t just live with it – you could potentially open up the handheld and replace the drive yourself. Valve don’t recommend this, though, especially not if you’re modding the Deck to fit a longer SSD design. The speed of the microSD slot has apparently remained untouched, so you could always rely on one of the best microSD cards for the Steam Deck instead.
