Well, what I would suggest you first is that you try the settings Thomas and I've posted in first pages of this post. Believe us, although settings looks pretty low it will load your GPU but saving some CPU power that is the main limitation here. These settings were validated on 1080ti and 1080 with i7 4770k and 2700X both OC. Of course it would work even better on 3600 or i9 9900K. You can try the Open Composite dll as well it allows to bypass Steam VR and saves quite a lot of performance headroom. There is a DX9 performance thread in this forum where you could mesure and compare your CPU performance with dozens of systems and see where you stand.