There was a now-deleted comment about the CPU busy-waiting for the GPU, to which I had this reply: Reviews/benchmarks of Flight Simulator by e.g. Gamers Nexus

There was a now-deleted comment about the CPU busy-waiting for the GPU, to which I had this reply: Reviews/benchmarks of Flight Simulator by e.g. Gamers Nexus show that Flight Simulator is heavily CPU limited, running on a single CPU thread.