Valve could be getting ready to make FSR 4 available to more players. The company added a custom FSR 4 DLL to Steam and the “Proton Experimental” compatibility layer, which could make it easier for games that already support FSR 3 to use AMD’s new upscaling technology. This change particularly affects SteamOS users on compatible handheld devices, including Intel Arc-equipped devices, and may also impact Valve’s Steam Deck and future Steam Machine plans. , YouTuber and hardware leak specialist, spotted this change and shared this information on Steam Machine and SteamOS users can “upgrade” games that support FSR 3 to FSR 4.
The file in question is “amdxcffx64.dll”, a DLL associated with AMD’s FSR 4 upgrade. Valve appears to have adapted it for use with SteamOS and Proton, which could reduce the reliance on third-party tools like OptiScaler, which some Linux gamers and Steam Deck users have previously relied on to force support for FSR 4.
As this new DLL is integrated into Proton Experimental, it could eventually work in many games that support FSR 3 on SteamOS and Linux systems. However, this support should still be considered experimental for the moment. If it works as expected, this would simplify the upgrade by removing, in many cases, the need to manually replace DLLs, crop files, or use additional launch options.
A head start for Steam Deck owners?
The version of FSR 4 added by Valve appears designed to support GPUs pre-RDNA 4, which is important for SteamOS hardware that doesn’t use AMD’s latest GPU architecture. AMD also confirmed that FSR 4.1 support would be available for RDNA 3 GPUs in July 2026, with RDNA 2 support planned for early 2027. Valve’s early work on Proton could therefore give SteamOS users a head start before wider official support arrives from AMD.
For Steam Deck owners, the situation remains uncertain, as the handheld console uses a custom APU based on the RDNA 2 architecture. Third-party solutions such as OptiScaler already allow players to forcibly enable FSR 4 in certain titles, but a Proton-level implementation would be a major improvement in terms of usability if it was found to be stable and compatible with the Steam Deck hardware.
For now, many Steam Deck owners are hoping that the new Proton Experimental support becomes available on the handheld console, and not just the upcoming Steam Machine.
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