I'm getting <10 fps after the 1st 10mins of the game when large amounts of units are onscreen. But even if I go to my base and its only my hero on screen, I still get <10 fps. 
This is true for ALL settings. I've tried lowest resolution with everything off and it still has this problem.
My computer spec:
AMD 3800
GeForce 7800x
4 gig ram
My spec aren't that terrible even if its on the low end but I should be able to have sustainable and playable frame rates. Yes, I have the latest video drivers...
Anyone else suffering with this problem as well?
Thanks! 