I've tried pretty much everything to get control of the GPU voltage. I almost gave up but today I tried to flash an Asus Radeon HD 6770 bios. GPU-Z showed for a while that the GPU was running at 1.2 V which means that the voltage is not hardware-locked. However even 2D was unstable, so I then used RBE to drop the voltage to 1.125 (Gigabyte default). Then 2D was fine, but I couldn't run 3DMark because "display driver stopped working..". So my theory is that the Asus bios has higher mem voltage or something and that my card can't handle it. Is there any way to drop the mem voltage with a hex editor or something? I think that might actually work. When I edit Gigabyte's original bios voltages, the GPU just stays at 1.125 even if I put higher values in RBE. Edit: The Gigabyte default bios also has "clock mode 0" (boot) which has voltage 1.2, but it's never used in Windows. Any way to force that mode to be used?