Voltage Prob

[x2 3600 rules sazakky]

I have an Asus M2N-E Sli AM2 board with an Athlon 64 X2 3800+. When I go into BIOS, it limits the voltage to 1.2volts and doesn't go any higher. I want the voltage to be about .1 of a volt higher as I can't overclock the processor to higher than 2.2ghz which is really bad.