its an addiction... I must sit on 4.5! lol
Very pure statement
That is a native AM3 mobo I think. I am not sure and may stand corrected. but I know one thing clearly and it is that AM3+ socket is designed for higher peak currents 145 Amps (I think) while AM3 can provide 110 Amps.
This difference does affect OC ceiling. an upgrade to 990 FX chipset might be a good option.
p.s a quality psu like a 750 W corsair will be a great option as well./ but I am honestly not familiar with your current psu brand and its quality.