One technical reason for why FSR 1 isn’t very good but works in everything is that FSR1 is the only one that just takes your current frame and upscales it, all the newer ones are all temporal - like TAA - and use data from multiple previous frames.
Very simplified, they “jiggle” the camera each frame to a different position so that they can gather extra data to use, but that requires being implemented in the game engine directly.
nekusoul@lemmy.nekusoul.de 2 months ago
Kind of.
The big thing that actually defines FSR2 is that it has access to a bunch more data, particularly the depth buffer, motion vectors, and also, as you said, uses data from previous frames.
The camera jiggle is mostly just to avoid shimmering when the camera is stationary.