While the support itself doesn’t necessarily mean OS-level toggle like the Steam Deck has right (which I believe is still at FSR 1), it still could be a nice touch for the titles that choose to implement FSR 4.
Maybe the community adds the OS-level support unofficially, somewhat similarly to Lossless Scaling right now (although perhaps for free). This is just my uneducated guesswork, please see this comment for proper expectations:
What exactly do you mean? Any link? As explained. FSR 2, 3 and 4 needs training data from the game. It is possible to swap DLSS out with FSR variants, because DLSS has the training data already. But you cannot have FSR 2, 3 and 4 on all games like FSR 1. And FSR 4 also has to modes as it seems, one classical Temporal like 2 and 3 that runs on relatively older hardware too, and the new ML-based variant that requires the new cores on RX 9000 hardware.
If you use Optiscaler, then I think what happens is that you swap the DLSS implementation with FSR 4 Temporal variant out. I searched the web a bit and found this: https://github.com/optiscaler/OptiScaler
So what part I was wrong about exactly?
You swap it with whatever upscalers it already has, yes. But not all games have any FSR or even DLSS support. Some only have XeSS, and you can replace that with FSR or DLSS using the utility. If it never had any kind of FSR support what-so-ever, how is it able to work at all?
I did not say this, where do you get that? I explained that FSR 1 is different from all other upsalers, it is not comparable to all of the other methods. FSR 1 is like a Photoshop filter, while the other methods have builtin data from game. You cannot add a Temporal Upscaler to a game that does not have any. You cannot use OptiScaler on a game that does not have any upscaling at all, it needs DLSS 2 or higher, or FSR 2 or higher, or XeSS, because those have the training data using Ai with the game builtin. You cannot use OptiScaler without any of these, or with FSR 1.
What exactly am I wrong about?
I am not saying you’re wrong, I’m trying to understand what you posted. But I see what you mean now. I was under the impression the training data was specifically for the specific upscaler so FSR4 would need at least FSR2 supported natively.
Oh, no no, I did not say or imply that. I was concerned about FSR 1 and the difference to the other upscalers. And the difference between the second new mode of FSR 4 that is not available on any other. So even if you have DLSS or FSR 3, you can only use the Temporal variant of FSR 4, not its ML-based variant (if I understand it correctly). At least that is what I said, so its probably true (self irony).