Low frame rate and flickering graphics

Does anyone have any helpful tips or links to threads that address low frame rate and flickering graphics?

I have 2 4830 ATI Radeon cards using crossfire and the graphics flicker like this:

I upgraded to a single Radeon 6870 and have been reading forum threads, installed ATI Tray Tools, followed the advice. I tried downclocking as well, no joy. Now in addition to the flickering, I only get about 8 FPS (this is in the starting zone, as far as I've gotten.)

It sounds like an interesting game, but I can't get past the flickering graphics. My heat appears to be normal, every other game (with the exception of Dragon Age 2) works fine. Running the 12.3 drivers. I also still have CCC running, can it run side-by-side with ATI Tray tools?

Thanks for any help you can provide.