Proton-CachyOS now supports OptiScaler through launch variables
Proton-CachyOS has added basic OptiScaler integration with its latest Version 11.0-20260506 release. The change brings OptiScaler into umu-protonfixes and Proton-CachyOS, which means Linux users can enable it through launch variables rather than setting it up manually in every supported game.
Proton is Valve’s compatibility layer for running Windows games on Linux. It is used by Steam and SteamOS, including Steam Deck, and combines Wine with graphics translation layers such as DXVK and VKD3D-Proton. Proton-CachyOS is a custom Proton build made for CachyOS, a performance-focused Arch Linux distribution.
Source: Github
Optiscaler allows gamers to swap upscaling and frame gen technologies
Our readers are likely already familiar with OptiScaler , but to refresh your memory, it is a tool that allows you to switch out one in-game upscaler for another. In supported games, it can redirect DLSS, FSR or XeSS calls to another backend. This allows users to experiment with newer upscalers such as FSR 3, FSR 4 or XeSS in games that already expose compatible upscaling paths.
The new Proton-CachyOS implementation is controlled through two environment variables. PROTON_USE_OPTISCALER=1 enables the feature, while PROTON_OPTISCALER_NAME=<name.dll> selects the injected DLL name. Supported names are dxgi.dll, d3d12.dll and dbghelp.dll, with dxgi.dll used by default.
Source: Optiscaler
When enabled, Proton-CachyOS can also use existing PROTON_<UPSCALER>_UPGRADE options to select which upscaler DLLs are downloaded. For example, PROTON_FSR4_RDNA3_UPGRADE=4.0.2 downloads FidelityFX DLLs for that version. The release notes also mention that PROTON_FSR4_UPGRADE=1 currently defaults to FSR 4.1.0.
The developer says it will not work with all games, and users should not report issues to the OptiScaler project when using this Proton-CachyOS integration. Manual OptiScaler setup is still recommended for users who need more control. We already covered VKD3D-Proton 3.0 adding FSR4 support to Proton, but this update goes in a different direction by adding a more automated path for OptiScaler injection.
AMD announced FSR 4.1 for RDNA3 and RDNA4
It may seem surprising that Linux is adding OptiScaler support now that AMD has announced official FSR 4.1 support for RDNA3 and RDNA2 GPUs . The issue is that AMD’s official support only covers desktop Radeon RX 7000 and RX 6000 graphics cards. RX 7000 support is expected with a July update at the earliest, while RX 6000 support will not arrive until 2027.
Source: AMD
AMD has not confirmed, even after our inquiry, whether this change also applies to all RDNA3 and RDNA2 GPUs, including integrated graphics. This means desktop, and perhaps mobile, discrete GPUs will support FSR 4.1 officially, while integrated GPUs may still require some tinkering. It should become easier once the official FSR 4.1 DLL files are released, though.
Source: Proton-CachyOS
