Hey!
The 2D settings for the voltage are wrong after a reboot. It gets set to the value from the 3D settings. And since I have them at 1,200V the low core settings in 2D somehow don't like that and the whole screen goes black when I open the usual programs (Chrome, Skype, Steam) after booting Windows 7. I tried setting the 2D value to different settings and save them, even changed them directly in the registry, but it keeps booting at 1,200V.
I guess it's a bug?
Using a different tool doesn't work because none of them allow changing the voltage because it's a Radeon HD 6950 DirectCU II.