Strange that raising agp volts would raise northie volts as well. You do know that agp volts go into the northie chip. But that it's not actually northy supply voltage. you would need to use a 500k ohm or 250k ohm variable resistor from pin 5 to pin 8 on the lm358 chip located left of northie to increase northie volts. Also instead of doing all that stuff you did why not just mod the lm358 chip next to that mosfet in your pic. The one right below and to the right of agp slot. Possibly pin 6 to pin 4 with a 50k ohm Vr would work. Seems to me it would work perfectly. If i didn't fry my ic7 from condensation i'd test the last one. But i'm fairly sure it'll do the trick.