amd crossfire freezes

[plopt]

I had no problems playing the trilogy with my amd hd 6850 card at max settings. As soon as I set up crossfire with an identical card I kept freezing up and had to dump the application through the task manager.
I've heard of others having problems with the amd cards and had success with work-arounds by disabling various settings in the amd vision engine control center. I haven't attempted this since it works fine for me with max settings, I just have to disable crossfire.