Ok, i have found the cuase of the problem. I monitored the GPU usage while playing a large battle and found rather odd results:
looking at the cenery with no men on the screen = 75% usage - 60fps (vsync on)
looking right at the mellee with heaps of men on screen = 10% usage - 11-20fps
the basicly explains it now to sit and wait for a patch. Iam not the only one
While i wait, does anyone here know what might be causing my GPU to only work at 10%? Only thing that would cause that is a massive bottleneck somewhere in my system but all other games run at 100% or close to it.