>>355874584
You would think that, but interestingly according to the frame inspector the issue is actually materials and texture interaction with the lighting. Basically, it's the CPU struggling on a single thread to send a frame. It's really bizarre. 

And you can kind of do that with OpenVR FSR, even on NVidia. 

https://github.com/fholger/openvr_fsr/releases/tag/fsr_v1.1 

This software allows you to use FSR on pretty much any steamvr game. It's one of the ways you can "cheat" a bit and get under the fill rate and get your frames back