uses the hardware-accelerated feature of the AMD RDNA™ 4 architecture
AMD FidelityFX™ Super Resolution 4 upscaling requires an AMD Radeon RX 9000 Series GPU or better and can only be used on appropriate hardware.
Requirements
[FSR 4 Upscaling] AMD Radeon™ RX 9000 Series and above
It’s possible they add compatibility at a later time (with reduced performance and/or quality due to lack of hardware acceleration), but they haven’t announced anything like that currently
https://gpuopen.com/fidelityfx-super-resolution-4/
It’s possible they add compatibility at a later time (with reduced performance and/or quality due to lack of hardware acceleration), but they haven’t announced anything like that currently
It’s not a hard requirement. Gamers have used the SDK to get FSR4 working on Steam Deck. Here’s a video of it in action.
https://www.youtube.com/watch?v=95N6-2U5YQo
TL;DW – It’s good to have as an option but not necessarily better than FSR3 on Deck due to tradeoffs. Depends on the game.