The HIP6031CB above PCI slot 1 controls the VCORE to CPU1. There is another HIP6031CB, on the bottom side of the motherboard right under the power connector, that controls VCORE on CPU0.
I've wired a 20K trimpot from pin 7 of these IC's (that is 2 seperate trimpots) to ground and am able to adjust the voltage around +10-12% or alittle over 2 volts. Make sure you start with the trimpot at the 20K setting (or use a 10K trimpot in series with a 10K resistor) so you dont start out shorting pin7 to ground.
IMPORTANT - measure the voltage at the points shown in the photos for both VCORE's. I believe that the voltages shown in the BIOS are for VCORE0 only. I found that adjusting the trimpot for VCORE1 had no effect on the BIOS reading but upon measuring it from the regulator it responded to the trimpot adjustments.
I now have my Athlon XP 1600+'s (1400mhz) running nicely at 1900+ (1600mhz) @ 1.99 volts
