I have read threads that discussed this topic on HD 6950 series in particular, however this issue is still persisting for me no matter what I try.
I have a rig running four shader-unlocked HD 6950s, on Windows 7 64bit, 11.12 Drivers with 2.5 SDK. Using ATI tray tools, I am able to adjust the voltage on HD6950 #0 and #1, however #2 and #3 remain at stock voltage (1.175 for my BIOS).
I have MSI afterburner 2.2 Beta 12 installed, with the EULA entered into the config, unofficial overclocking 1 (also tried 2), further up the config file, unlonlockvoltagecontrol=1 and unlockvoltagemonitoring=1 too; after I launch the app, I go into setting and also check unlock voltage monitoring and control there (just doing it in the config file does not change it in settings, nor does changing it in settings change it in the config). No voltage control for any HD 6950... nor do I even get to see the voltage...
Tried Sapphire TriXX, cannot even use the slider for voltage, it is locked.
Tried Radeon BIOS editor, and changing only the voltage of high performance profile to 1.1 (still higher than the other 3 profiles), I did not change any clock settings or anything else in RBE, saved BIOS and flashed it to one of my four cards; BSOD at boot, every time, every card.
I am able to run 920MHz at 1.075v, or 935MHz at 1.175, MH/s gain from 15MHz is not worth the power usage, or heat increase at 1.175v.
Does anyone have any tricks or tools that I have not already tried? Any help is appreciated, I will offer a couple BTC reward to anyone who can solve this.