I've been through every imaginable scenario with my 7950 Windforce card.
I've tried 3 bios's for this particular model with mixed results.
The original Z.. bios is unstable like most others have already stressed about.
F43 is stable, but the voltage lock maxes out at like 1.08mv. So, that limits your OCing ability.
I could not push it over 1090 on the core and 1400 on the memory without some form of lockup in the system.
If I went over 1090 on any bios, the machine would lock up within 10-15 seconds in Heaven.
My ASIC is 61.4%, and I still don't know if that is good or not.
Here is where I tried something with blind luck:
I downloaded the Gigabyte bios F62 for the 7970 model similar to this one since the 7950 uses the 7970 pcb and all...
I just overwrote the junk Z... bios that came on the card and kept the F43 as my backup.
It booted up and had to reinstall the drivers due to it now being seen as a 7970.
*No, it did not unlock extra shaders or ability to change the voltage in Afterburner*
BUT... Trixx allows you to adjust the voltage from 1.256mv that is the standard setting on this 7970 bios to anything below that.
So I started off brave. I jumped right to 1100 core and 1500 memory. Ran Heaven for about 15 minutes with no hickups at all!!!
I bumped it up to 1150 core and 1600 memory. Ran 15 minutes on Heaven like a champ.
I finally just finished another 15 minute run on 1200 core and 1600 memory with no issues.
I am a bit nervous of how far I can go from here, but I did want to jump on the boards and report this beauty of a find!!
Another thing that is helping out is that I replaced the cooler on the 7950 with an Arctic Accelero Xtreme 7970. My temps under full load max out at 56C overclocked. Idles at 30C.
Here is a link to the 7970 bios I am now running: