These are all solid assumptions and I thank you for providing the data to try and manage expectations here.
However, I do think you're making the case for the current state of things as opposed to what AMD is apparently trying to achieve by supporting older hardware with FSR 4.
That said, it's probably going to be somewhere in the middle, with RDNA 4 (which Steam Deck APU is not) getting the full potential that FSR 4 can provide, and RDNA 2 (which Steam Deck APU is) seeing at least some of it. I wonder if the latter is going to be of any benefit compared to what Steam Deck users have now, especially in terms of the power draw, like you mentioned.
brucethemoose@lemmy.world 5 days ago
“Supporting” and “working well” are different things though.
Without the low precision/specialized instructions of newer hardware, there’s just a fundamental limit to what can be done without the overhead of FSR being too much. Though there are certainly some implementations that could work on older hardware, I’m sure.