lol , well that card isn't meant for graphics at all man and 3dmark05 taxes the HELL out of cards.
Doubt it, like said if you haven't even noticed any stability issues I wouldn't worry about it. If you start getting random reboots or freezes then you can start to worry. Otherwise it could just be a misreading of the voltages.
But yeah...300 sounds about righ
I only get like....1000 I think, I got an FX 5700 but I think it's mainly the CPU that helped there.