Weird kind of bottleneck with 4090 and Intel 13th i9 in Cyberpunk 2077 VR

[Glazarus]

I've been struggling with the classic-never-to-be-fully-solved-nvlddmkm problems and I've seemingly ended in a pause on those issues so I thought I'd try out my new 4090 Strix with some VorpX VR modded Cyberpunk 2077. I started turning off raytracing and setting everything else to max/ultra with no DLSS. This seems to get the 4090 up to 95-98% usage and my CPU at 60%, creating some spikes in VR which shouldn't really occur unless the GPU is at full 99% bottlenecking. 

But the odd thing is that when I put everything down to the lowest setting, DLSS to ultra performance, the GPU graph in VR shows just 0,4ms for the GPU and the usage was just 50% and the CPU had a usage of 40%, but the framerate ends up at 75-89, far under the 120 fps mark that I need to reach to get a good experience in VR. 

What's even stranger is that when I alt-tab out of the game to check the activity monitor for the graphs, both the GPU and CPU spikes their use to 50%, while in-game they just settle down below 35-40% usage. That should logically be the other way around.

 

I have no idea what is causing this. It's like there's something else bottlenecking everything. My PSU is a Corsair HX1500i 1500W but with this bottleneck I'm rarely getting anything over 300w. 

So what is it that causes this? I'm getting 500fps in Heaven Benchmark 4.0, so there shouldn't be a bottleneck like this. I'm not sure what's causing this. Turning everything to low in cyberpunk should easily generate the max 144Hz that the Valve Index can do, but it's just stuck there at a max 89-90 and dipping all the time to 75.