I've checked that on my last flight ... the 1080Ti is running cool as a breeze and fluctuate between 10% and 20% VRAM used.
This is weird in a different way. It seems a bit low. Is as if the simulator or the driver, doesn't even try to use all your VRAM. I have a 1080Ti too, and while sitting on runway 10C at KORD, I have the following figures, with DD Chicago City X installed too and sitting on 10C, I can see the detailed Chicago Skyline in the background.
- With a default aircraft and 0% AI, I have 5.5 GB out of 11.0GB of VRAM used, with GPU utilization at 55% and CPU utilization at 30%
- With a default aircraft and 100% AI from UT Live, I have 5.6 GB out of 11.0GB of VRAM used, with GPU utilization at 39% and and CPU utilization at 30%
- With a PMDG 747-400 and no AI, I have 6.4 GB out of 11.0GB of VRAM used, with GPU utilization at 44% and and CPU utilization at 30%
- With a PMDG 747-400 and 100% AI from UT Live, I have 6.4 GB out of 11.0GB of VRAM used, with GPU utilization at 32% and and CPU utilization at 30%
What might seem to be odd, that with full AI traffic, the GPU is less occupied than with no traffic, might possibly be explained with this: when the system is less taxed by other stuff, like AI, the GPU is free to do more of its own stuff, like running Shaders, so it's being used more.
In general, is healthy to have a medium-high GPU utilization, it means the graphic products you are using DO take advantage of the GPU, and a fully PBR scenery like this surely will. It's just important you don't get in a situation the GPU is *too* stressed out. If the usage is higher than 90%, you'll probably know it's time to lower your settings.
But you also don't want it to be too low either, because it means the application is not taking much advantage of the GPU, so it all fall back on the CPU. Which seems confirmed in your case, since you have a much lower GPU utilization compared to mine, but a much higher CPU utilization.
Have you maybe tweaked something in the AffinityMask settings ? I have everything default, and I disabled HT in the BIOS, which seems to be the best choice for P3D4, especially when stuttering is concerned.