Kinda backwards...
You should increase your FSB (aka CPU Frequency, HTT, Hypertransport Frequency), THEN increase your voltage IF NECESSARY, to increase stability.
FSB/multiplier increases bring increased performance, voltage brings increased stability.
Figure out if your cpu and ram will boot at a frequency, then benchmark and stress test to see if it's stable. If it is unstable, slightly increase your voltage. If increasing your voltage doesn't bring stability, something is probably maxed out. Could be RAM, motherboard, or CPU (or PCI bus and components if you can't lock your PCI freq)