for me the GPU & CPU runs under full screen (FHD) at full load.
The graphics setting does not matter.
If I switch to “Window”, I can also switch to “Ultra” (FHD).
Then the utilization in buildings remains at approx. 40% GPU / CPU.
On the map is locked at 95% GPU / CPU.
My system is out of date
16 GB RAM (DDR3)
GTX 1060 (3 GB)
Driver: Nvidia 471.41
Storage: SSD 860 EVO