I do have the same issue using my reference 7900XTX with Ryzen 5 3600 and the HP Reverb G2. It struggles in all OpenVR titles. OpenVR benchmark produces 26.8 FPS and stutters like hell. GreenHell VR is the worst, completely unplayable, frame time counter is in full red with purples every 5 seconds or so ~38-45ms, which is a shame. Half Life Alyx can be fine tuned a little bit by fumbling around Windows Mixed Reality for SteamVR settings, but it still underperforms the 6900XT.
Using OpenXR things look better, for example BoneLab performs well, running totally smooth on low! graphics, but I have waited much more from this card.
2D performance is great without any doubt. Every newer demanding title plays well, and in ray-tracing it is also slowly catching up to a usable level with the new drivers.
I have seen some progression in the right direction with the two new driver releases (two releases in one month! which is great), the issue with the Valve Index has also been solved, so I suppose we can also get something, who mainly would use the GPU for VR.
I also wish that AMD could put this issue even higher on their known issues list.
The Community manager has promised feedback about this issue in this discussion:
https://community.amd.com/t5/graphics/7900xtx-low-performance-in-steamvr-and-vr-in-general/m-p/56739...
