My ASUS 7970 DC2 is pulling 700 MH/s at stock voltage. It takes up 3 slots so you have to be willing to part with the space, but it does a really good job at keeping the thing cool, which goes a long way to stability. I'm looking at about 165W.
That is a very nice average. Is this the "TOP" factory overclocked version or the ref/directCU II?
165W also sounds significantly less than what I have seen benchmarked. Did you change anything?