@patrik
Ahh, damn... Can you imagine I didnt even try 50Hz? Default seemed to be 49Hz and I was messing with it and well over that.
Anyway, 50Hz seems to do the trick, thanks.
Edit: On further check, it seems it's much much better than before, but there still is some tiiiiiny problem ;-) Not noticable, unless you're looking for it. So, there might be some magical values to get it right, I guess for both vertical and horizontal refresh?