I have found that flashing the default ATI 7950 Bios to any 7970, reduces the power consumption substantially, of course at 925MHz clock rates. I have noticed using a DMM that he 7950 Bios reduces the VDD to around 1.02V and is useful for Linux based mining rigs, since I could not find a software to control voltages of Tahiti based cards in Linux.
How is the success rate on 7950 flashing?
100% success on XFX Double D 2 cards
100% .. on Reference 7970 4 cards
0% .. on MSI Twin Frozer III (ATIWinflash crashes midway, tested 5 times using both Win 7 and Win XP)