Valve adds AMD FSR4 DLL to Proton Experimental

AMD FSR4 appears to be coming to Valve’s Proton Experimental. The change was spotted by Brad Lynch, who found AMD’s FSR4 DLL in Steam files linked to Proton Experimental.

I told you so. As soon as we saw experiemental FSR4 flags in Valve files it was obvious taht Valve is working with AMD to bring newer upscaling support. That work now appears to have landed in Proton Experimental, with the FSR4 DLL added to Valve’s Steam depot.

SteamDB shows fresh Proton Experimental bleeding-edge manifests dated June 22. The app is listed as “Proton Experimental” under app ID 1493710, with its main Linux 64-bit content depot listed as 1493711.

FSR4 DLL spotted in Steam files

The file in question is “amdxcffx64.dll.” This is not an open-source FSR release. It is a binary DLL used by AMD’s FSR4 upgrade path, which has already been used by community Proton builds and OptiScaler setups.

This is still tied to Proton Experimental, not the regular Proton Stable branch. Valve’s public Proton changelog does not mention the FSR4 DLL yet. The latest public changelog entry only says Proton Experimental was updated with new development versions of vkd3d-proton, dxvk, vkd3d, dxvk-nvapi and FEX.

The timing is interesting because AMD recently confirmed a wider FSR Upscaling 4.1 rollout. Radeon RX 7000 series support is planned for July 2026, while Radeon RX 6000 series support is planned for early 2027.

Source: AMD

I was not able to download the file through the Steam console on Windows, but perhaps some of you will have more success. AMD has not confirmed FSR4 support for RDNA 3 or RDNA 3.5 graphics outside discrete GPUs. It only mentioned Radeon RX 7000 and Radeon RX 6000 series. However, the Steam Machine uses a GPU powerful enough to be compared with Radeon RX 7600M-class graphics based on Navi 33, so it should be included.

Source: SteamDB , Brad Lynch

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