Maybe it was GigaBytes way to fix the powerplay clocking change problems. LOL
This BIOS investigation all started after my 'working perfectly for months' 5870's began crashing the PC when YouTube videos were played. Seemed to be the Powerplay versus flash (UVD?) issue encountered by many. And I could not really tie it in to the Flash Player 10.1 update 100% for sure as far as the date of the update. But I thought it was that.
The other last thing I changed before was trying out Cat 10.6 (when it came out) after having used 10.4a Preview ever since those came out. The 10.4a seemed to be totally fine in every way (for me), but the 10.6 caused other crashes (grey screen, bluescreen reboots). But a total driver clean out and going back to 10.4a did not change it back to all working fine like before!
Uninstalling Flash totally, and reinstalling the latest version didn't help either.
Turning off Flash HW Accel did stop it occuring though.
I have just tried Musho's Bios edit and that does not help either - but when I edited that to have a constant 1200MHz memory clock, it did fix that Powerplay/Flash (UVD?) issue. And now I can use HW Accel fine with Flash.
It seems, from forums I checked, that the real issue with Flash is ATI's fault (Powerplay) but Adobe help it work better by altering the ATI clocks themselves when Flash is used.
So it does seem to me that it IS all ATI's fault, with Powerplay... and now mine is all working fine - so far....
Now I want to have a new fan profile - which I did also change in my BIOS edit, but it is not used. It still seems to run at the same default temp/speed sequence. I set the Min to be 40% but it runs at 21%. Mine is set to hit 100% by 70degC, but it actually isn't even over 30% by 70degC. So the BIOS edit is not being used.