I too am convinced that these issues stem from voltage. I have seen this error occur once since I have had my 7950, and it happend when I accidentlally alt + tabbed out of SWTOR whilst it was loading and into a youtube video. The MSI afterburner graph on my second display was showing the card flicking between 2d and 3d clocks, presumably causing the voltage to change quickly.
Never seen it happen again though.
Never seen it happen again though.