When you did a fresh w10 install, did you go to the vendor site to get the latest driver? I noticed that it doesn't actually install the latest one when it picks one for you. I realise you probably did, but just checking since I seem to have missed you mentioning that explicitly.
For the fresh environments I installed the latest drivers from direct from NVIDIA for the GPU ... everything else I just left with whatever defaults it picked up.
I play games on Windows 10 Pro x64 and PA is the only game that has issues with performance. Both the framerate and simulation speed suffer when the battle with multiple AIs gets busy. This is on 6700K, 32GB of RAM and GTX1080 The CPU gets completely maxed out and the simulation speed drops to 30% sometimes and framerate as low as 20fps. I can only play with 4 AIs and 2-3 planets. Ashes of the Singularity doesn't even hiccup with 5000+ units on the screen, although is not nearly as fun as PA.
This thread is about lower performance on windows 10 than on windows 7 / 8. What your describing is normal behavior of PA. It's not really fair to compare to AOTS- that game has been built from the ground up to showcase the oxide engine- an rts engine built around mantle and dx12 to maximize thread usage with large unit counts. Those technologies didn't exist until after the PA engine was built. Also AOTS is a much simpler game, it's a fairly standard top down rts so is simpler to simulate that a whole solar system.
