I know, the title is a little odd I have a pretty high end system including an ASUS GTX 3090. When I set up my VR environment and turn on the Debug Tool performance HUD, it shows me constrained by the GPU and it shows performance headroom as a large negative number. This is even before I try actually taking off and flying.

I don't understand how that could be and I don't know what to look for. It seems like I should have lots of performance headroom when I am in VR but not flying yet.

I need guidance on how to troubleshoot this GPU bottleneck. I have tried many things but something is not right and I don't know what.

I have an i9-10900 processor, ASUS 3090 GPU, 32GB of 3600Mhz ram, and all M.2 and SSD drives. I am using a Quest 2 with Airlink and I am using a dedicated 5Ghz wifi channel for it.

 

Just to add some more info: This is happening just sitting on the home screen, not in VR and not even with a plane loaded. I have the internal developer mode turned on. It is showing I am limited by my GPU and the GPU part of the screen at the bottom is showing all yellow and response time average of about 30ms. There has to be something major wrong with my setup for this to be happening.

 

Please help.

Edited January 13, 20224 yr by Rob G
More info added

What happens if you load a plane?

The home screen is gpu limited, I believe.

Yellow seem pretty normal. Green means 60 fps or more and to get this level of fps in VR, you need to reduce the resolution to the point where the experience in Vr is not good. So we dont even dream about a green graph in vr at least for the GPU. On one flat screen, you will probably get easily a green graph depending of your screen resolution. I maintain 70 fps on a single screen and all graphs are green.

Yellow means that you maintain 30 fps or more. Most people in vr tend to adjust to maintain 30-32 fps for a smooth experience so yellow is what you expect to see.

With your type of system, its normal to be GPU limited as the CPU is much more powerfull than required to feed 30. images per second to your GPU. On my system which similar to yours, the gps graph is yellow and represent a stable output with no variation in the red zone (red is less than 30 fps). My main thread and my render thread fps graph are a mix of yellow and sometimes green which means the processor have no problem feeding my card to the limits. When I observe my GPU and my CPU load, the GPU is 90% and more while the CPU is at 25%. My most used CPU core goes to 70% from time to time but there is still headroom.

So the yellow is not an issue especially if the flight is smooth.

 

What happens if you crank Lod to 400?  Or is it already there?  I try to make my sim alternate between main thread and GPU limited.

Have you set "prefer maximum performance" in the Nvidia control panel?

1 hour ago, ryanbatcund said:

I try to make my sim alternate between main thread and GPU limited.

A recipe for stuttering 🙂