Valve is about to slash the file sizes of the Steam Deck's SSD-hogging shader caches in half

Here's some exciting news for those of us with smaller Steam Deck SSDs or choice paralysis over what games to uninstall. A forthcoming update to the Steam Deck's open source video driver will shrink the gaming handheld's shader cache files by approximately 60%, Valve has confirmed to PC Gamer. 

A recent report on Phoronix highlighted an update coming in Mesa 23.1, which "re-implements the RADV pipeline cache based on the common vk_pipeline_cache." There are probably a whole bunch of words in that sentence that don't mean much to you—most importantly, Mesa is an OpenGL and Vulkan video driver that Valve, AMD, Intel, Microsoft, and others contribute to in a rare act of unity, and this change affects how the now widely used Vulkan driver caches files.

In the Steam Deck's case, Valve has created big shader cache files for individual games that are delivered during the installation process, improving performance and helping avoid the dreaded shader compilation stutter. The downside to these shader caches is how much space they take up: potentially multiple gigabytes for larger games. With the new Vulkan pipeline cache, however, they're about to get a lot smaller.

"In combination with single-file disk-cache, this reduces the cache size by ~60%," the summary on Gitlab says. I emailed Valve's Pierre-Loup Griffais to confirm this applied to the shader cache files on the Steam Deck. "That's our expectation for pre-built shader caches," he confirmed. Griffais did add that some games won't see their cache files shrink quite so dramatically, because the update "Won't change anything for the size of transcoded video depots, which are also marked 'shader pre-caching' in the UI."

So when should we expect this update to arrive? The stable version of Mesa driver 23.1 is expected to land in early May, and we know that SteamOS 3.5 is also on its way soon, including a graphics driver update. I expect these two things will coincide, first in a beta SteamOS release and then in a stable release early this summer. It's going to be a good season to hang out in a hammock and play your Steam Deck, at least if you're in the northern hemisphere. 

If you expect you'll still be tight on space even after this update, though, here's our walkthrough for upgrading your Steam Deck SSD.