4Ghz
Turns out 4GHz is all I can get off this particular chip at reasonable voltage levels. At this point I was already at 1.39 vcore. If I put it under water I could probably get 4.2-4.3? This particular example just isnt a very good clocker.
Still, I got 79ish Gflops out of it. I was getting just under 50Gflops out of my 4GHz 920, so it is more than 1.5x the power.
In theory.
I should note, those temps are 'under duress.' I unplugged the side fan and the puller fan on the cpu cooler (top fan); then I laid a cd case on top of it. So it just had the pusher and the rear fan.
Did pretty well for nearly 180W. I noticed the rear fan actually started pulling hot air out after I did this, so it seems to be able to help take up slack in a failure.
Another interesting thing I noticed was, while I was playing around with unplugging a cpu fan I ran just the puller and had the pusher unplugged. This actually ran cooler by 2-3C vs just the pusher. I didnt have the CD case blocking it at this point though. This requires further testing. I had been running with the assumption that pushing air through a cooler would run cooler vs pulling air through it.
Anyway, with it setup the way it normally runs, max temperatures under this stress is in the 70-75C range.