Turning on FSR 2.0 doesn’t seem to improve framerates using an AMD RX 7900XTX at 4k. I am GPU bound but turning on FSR quality gives me maybe one or two frames instead of maybe 30-40% as it should be. This is also confirmed in this benchmarking video here: https://youtu.be/vfI2CIcqWII?t=479 (timestamped)
You can see in the video that the RTX 4090 with DLSS on gives the expected performance boost, but the AMD RX 7900XTX gets almost no improvement in frame rate with FSR on. This is on the PC game pass version with the latest AMD drivers.