VKD3D-Proton 3.0 release paves way for AMD FSR 4 on Steam Machine
VKD3D-Proton, one of many compatibility components used by Valve's SteamOS (among other Linux gaming initiatives) has recently been updated to version 3.0, which adds support for AMD FSR 4 upscaling to "ship FSR 4 in a more proper way in Proton".
What's most interesting about the addition is that while the default build only enables the feature when using it on an AMD RDNA 4 GPU or newer, there are flags to enable emulation of AMD FSR 4 on GPUs with INT8 and Float16 support. This is very much akin to the FSR 4 mods we've seen in the wild enabling AMD FSR 4 on AMD RDNA 2 and RDNA 3 GPUs, which were reliant on the leaked FSR 4 Int8 DLL to function. The patchnotes describe the decision not to include this emulation path by default as "over my pay grade", but it means that users of AMD RDNA 2 and RDNA 3 GPUs on SteamOS now have a way to enable AMD FSR 4, which could bode quite well for Steam Machine and Steam Deck alike.
One comment that lends further credence to the idea that this will lead directly to AMD FSR 4 support on Steam Machine—besides the fact that forcibly enabling it should now be possible no matter what—is that Valve remarked to Digital Foundry the desire to have official driver-level FSR 4 support from AMD. The hacky INT8 FSR 4 methods required on Windows (and now Linux) have a performance trade-off compared to FSR 3 in order to achieve cleaner visuals on older RDNA GPUs.
While the powerful Zen 4 CPU within the Steam Machine should help it maintain higher framerates with the help of FSR upscaling, this performance drop could be problematic for Valve's stated goal of 4K and 60 FPS for every Steam game. Some degree of official support will likely be needed to prevent FSR 4 from being too demanding on graphics performance, and that's not even getting into the wrench sure to be introduced by RT-required games like Indiana Jones and the Great Circle.
As we've recently seen from testing of a broadly-equivalent Steam Machine PC build, GPU performance remains the chief concern ahead of Steam Machine's launch. The strengths of SteamOS for gaming, the power of Zen 4, and other factors may still see Valve ship a true PlayStation 5 competitor. And considering PSSR only works on PlayStation 5 Pro, native driver support for FSR 4 on Steam Machine could be just the ace Valve needs.
