I'm afraid this is very likely to be another case of the suspected game engine bug as I describe here

Tandruil9 said: Only changing ingame and after restarting did the fps lock seem to work.Are you only seeing fps of 60 or less in the game now?
Tandruil9 said: However when my whole group started again and some of them created their own rulers it crashed once again.The whole PC still? Or just a game crash this time?
"setting_framerate_cap"={Was it not possible to set this to 60? What we are trying to achieve here is restrict the game to 60hz ; what fps do you see just ... Read more
version=0
value="165"
}
"setting_framerate_cap"={Did you set the frame rate cap to 60? What fps are you seeing in the game before it crashes?
version=0
value="off"
}
ecosamo said: Is there a way to keep the cores I deselected from turning themselves back on?I'm no Windows expert, but a bit of googling found the idea that you can set the Affinity on steam.exe , then when you run the game from there it should inherit that setting. I also found mention of a utility called Lasso that will do this.