core voltage control software?

[KamiDisturbed]

I wonder is it possible to change the core voltage via software like changing clock frequency with Clockgen?
(Like with clockgen you need to use PLL code you can find in motherboard to use it for changing the clock frequency of cpu.)
If changing core voltage with software is possible i would be able to clock my HP compaq 5750 better, since the bios is locked with no options to overclock. I already was able to increase the clock frequency from 2,3ghz to 2,35ghz but increasing it further makes it unstable. I also heard that HP's motherboards are very hard to hack and make bios mods out of it, but if it would be possible to make an mod out of this bios it would be even better option for me.