Solder wires to Pin 7 and Pin 10 of the IC that controls the voltage to the CPU. Put a 47K trimmer (49 cents at Radio Shack part # 271-283) between each wire and ground. Use a spade lug or loop under a motherboard mounting screw for your ground connection. For convenience I suggest you mount the trimmers on a piece of breadboard and secure it to your motherboard tray with Velcro.
Pin 7 controls the voltage, Pin 10 controls maximum voltage threshold. Turn the trimmers to full resistance boot your PC and start VIA Hardware Monitor. Set the polling interval to 2 seconds and slowly dial up the pin 7 trimmer until the voltage peaks. This should be about 2.1 volts. Then dial up the Pin 10 trimmer until your screen blanks and back it off a tad. Your PC will probably reboot when the screen blanks. Go back into VIA Hardware Monitor and dial the Pin 7 trimmer up to 2.3 volts. You may be able to go higher but I don’t recommend it.
Caution this will stress your cooling. Be careful or your CPU could end up a crispy critter. I also suggest buying a third hand device from Radio Shack to hold a pre-tinned wire to the IC leg while you solder. The magnifying glass on the third had will come in handy too. Get in and out fast so you don’t toast the IC. Lay off the caffeine and if you are of age, have a beer a half hour before soldering to steady your hands.
I’ll monitor this thread incase you have further questions.