I know why you guys are having probs with the new drivers. You have to change the voltages for the other voltage Powerstates too, not just "3D". There are 2 additional power states for UVD decoding mode, and crucially "overdrive" mode.

Before 7.12, enabling overdrive in CCC activated 3D mode only, but afterwards they fixed it to use the overdrive setting (which might have been set higher than 3D on some factory OC'd cards)