Simple GPU miner with 1x 5850 and 1x 7970.
Pulls 370 watts at the wall with some tweaking of the GPUs.
59C for the 7970 and 68C for the 5850.
850 Mhash/s
P.S. Picture was taken by Potato 2000
One 7970 can do ~700, one 5850 can ~320 easy
I don't like to mess with overclocks, it would get quite hot in the garage, instability issues, temperature issues, and high power consumption.
The higher hash rate vs power consumption isn't worth it. In the end you'll have accelerated electromigration and dead cards.