While clearly the game is doing something that is making your GPU run at higher utilization than it probably should, it can't make it run at any more than 100%. You should be able to run your system at 100% CPU & GPU utilization indefinitely without overheating or you risk damage when you encounter something like this (probably a bug) or stress testing, etc.
This ^^
If you cannot run at 100% CPU/GPU then your airflow/cooling is not sufficient unfortunately. From what I'm reading and what I've seen with temps playing with my GTX 780 - D:OS seems more GPU bound than most games. My CPU is usually much more worked temp wise than my GPU for most of the games I play. It's not the case with this game, my GPU temps are higher than my CPU temps ~69/55.
Getting some pretty low CPU utilization, here ~7%-15%, likely due to it actually appearing to spread the load over my cores.
So I do think you need to focus on cooling your video cards for this issue, but it doesn't hurt to monitor your CPU temp as well.
Good luck OP.
