Valve's Proton Test Build For Steam Machine And Linux Gaming Adds FSR 4 For RDNA 3

Not only was the Steam Machine just launched on the Steam storefront, but a quiet Proton Experimental update has enabled AMD FSR 4.1 on AMD RDNA 3 and RDNA 3.5 GPUs.

Similar to previous community tweaks done with a leaked version of AMD FSR 4, this version of AMD FSR 4.1 uses the internal INT8 version rather than the FP8 version. The INT8 version works on more GPU architectures than FP8, but does incur a higher performance penalty.

Valve just added the version of AMD’s FSR4 that was announced last month and adds support to older GPUs rather than just RDNA4

This DLL file, added to Steam, and coming to Proton Experimental will likely allow Steam Machine/SteamOS users to “upgrade” FSR3 supported games to FSR4 pic.twitter.com/kNNhMDS34D

— Brad Lynch (@SadlyItsBradley) June 22, 2026

Even so, INT8 FSR 4 is preferred by many users of older AMD GPUs thanks to its superior motion stability and image quality compared to AMD FSR 3.

While Valve had seemingly jumped the gun with this move by releasing the update yesterday, AMD also officially enabled AMD FSR 4.1 on RDNA 3 GPUs just hours ago, leading us to believe AMD and Valve may have worked together on this. AMD's Windows GPU driver is limited to desktop Radeon RX 7000 GPUs, but AMD also notes that "lightweight machine learning models" are under development to extend the feature to iGPU users later.

We power over 1 billion gaming devices worldwide.

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Today, we're bringing @AMD FSR Upscaling 4.1 to Radeon RX 7000 Series graphics cards, extending our latest machine learning… pic.twitter.com/bpVHmQ7l0b

— Jack Huynh (@jackhuynh) June 22, 2026

Even for players outside of Valve's hardware ecosystem, this is good news. Linux gamers can now utilize AMD FSR 4.1 on RDNA 3 and RDNA 3.5 GPU/iGPU hardware, and Windows gamers can now enable official FSR 4.1 on RX 7000 GPUs.

For the Steam Machine, FSR 4.1's image quality is nigh identical to PS5 Pro's (AMD-developed) PSSR upscaling, but unlike PSSR, can leverage Frame Generation. With AMD FSR 4.1 upscaling and Frame Gen in tandem, the Steam Machine should outclass the base PS5 and compete favorably with the PS5 Pro, making that $1,049 MSRP more compelling.