Howdy,
I am running urw 3.50 b2 on win 10. I have fairly cutting edge hardware. i5, nvidia 1070, etc. I am also running the steam version of the game. When zooming in and out of the terrain and world maps, the loading goes VERY slowly. There is also lag when fading in and out of sleep. Tasks take far to long to complete (cutting down a tree etc.). Alt- tabbing seems to have some sort of effect on the framerate. I am running several simple item mods of my own design as well as caethans mod. If you need any other info let me know.