I did a quick test, with SteamVR Home and Project Cars 2.
The FFR effect is visible in SteamVR Home on the trees, there is a circle in the center on the vision where they look normal, outside of that they are more grey. Maybe FFR is not compatible with all kinds of shaders? Normally, it should only make things look more blurry/blocky, not change the color.
I could not see any positive effect on GPU usage, and it double the CPU render time.
In Project Cars 2, I could not see any artifact, and could not see any effect on performance, positive or negative. I suspect it wasn’t active. Actually I could have checked in PiTool, it shows the status of FFR, but I’ve just realized that. EDIT: It wasn’t ON, I checked.
So, not impressed so far. It’s only a beta after all, I’m curious to see if it can be improved.
I’ve also tried IL-2 Sturmovik: Great Battles (aka IL-2 Sturmovik: Battle Of Stalingrad).
Looks promising in the menus: no CPU overhead, Aggressive FFR halves the GPU frame time, and it’s hard to notice the artifacts. I had to offset the HMD horizontally to see the pixelation in the sides.
Sadly, the game crashes once I get in a plane.
With this edit, I can update my first impression to “potentially impressive”. Now I just need to find a game where it works!
I’ve tried DCS. It works, effect on GPU is slightly positive: it shaves 1-2 ms off the GPU frame time. I’m limited by my CPU (an overclocked 4690K) in this game anyway, and FFR wasn’t going to save me. There the FFR settings seemed to be flipped: Aggressive was only noticeable on the sides. Easiest to notice it is to look at the comms menu. Balanced and Conservative were unusable, too pixelated, too close to the center of vision.
I’m using PiTool quality 1.5, 72Hz, and resolution between 2000 and 3000 lines depending on the game.