I've recently been experimenting with LinX 0.6.4 as a stress tester, and using that along with Prime95 I've had to make some minor alterations to my voltages.
Going to be changing my case and adding another HD 6990 to by set-up as well as Watercooling the CPU and both GPU's in separate loops. Will post some pics and temp results in a couple of months or so once completed.