Fsr performance almost doubles the framerate, but Quality offers up to a 35% boost. Something like horizon that runs at native 4k 30 fps can now run at 4k 40 fps at the same resolution. With fsr performance they should easily be able to hit 60 fps at 1440p quality fsr.
Yeah but FSR Performance also kinda degrades the visual quality so I don't see many developers using it.
I can, however, see more games using FSR in both quality and performance presets (as they are right now already) so they have more GPU room available to push other effects.