I noticed that there is an area in the game where the CPU usage is - strangely - climbing at 100%, even if there is no animations or anything that should be demanding : the tactical positioning main window (where are listed leaders etc.). Strangely even the main map is far less demanding (something like 30% for me), and the battle in grid-mode (30% too, even when particles are displayed).
So it smells like some loop is running at an infernal speed somewhere in the code, and I'm unsure why something like that should run like mad, for a window without anims.
In case you wonder, I do care about cpu cycles, as I play on a laptop, and it triggers all three of my PC fans, thus a big noise which annoy me like hell