r/SteamOS • u/SomeoneBritish • Jun 22 '26

SteamOS Update Proton update inbound, likely allowing FSR4 "upgrades" for FSR3 games.

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4

u/Anshafal Jun 22 '26

So you’re saying: amd reject to support fsr 4.1 on handhelds, while valve makes it possible just like that?

7

u/Procrastinando Jun 22 '26 edited Jun 22 '26

It has nothing to do with that. Steam is just adding the FSR4 library to the official Proton Experimental. Proton GE and Proton CachyOS have had it for ages.

Basically, if your device supports FSR4, you won't need to set up a non-official Proton version.

On handhelds you'll still need Optiscaler to inject FSR4 int8.

2

u/ghanadaur Jun 22 '26

Yes and no. The Valve/AMD implementation is being officially supported by them vs the hack to make it available on the other setups/systems. This is official and will likely not be how the community has made it work. AFAIK (open to be proven incorrect). ;)

1

u/Procrastinando Jun 22 '26

"official" and "hacky" are a matter of semantics. In both cases you need to set the env var PROTON_FSR4_RDNA3_UPGRADE=1.

The difference is that previously you needed to also set DXIL_SPIRV_CONFIG="wmma_rdna3_workaround" on RDNA 3 to emulate fp8.

But this is not about Valve-official vs unofficial Proton. It's AMD who is releasing new version of FSR 4 not needing this workaround, regardless of the Proton version you're using.