I have the XFX 780i nForce which looks very close to your MSI nForce MOBO, so hopefully things are in the same place;
The 780i pic shows you where to do the VDroop Mod. Start first with 3-4 pencil strokes. Look-up the volts and if your Bios and CPUZ volts are close then add one more stroke and so forth. If your CPUZ VCore goes higher then the Bios VCore, no prob, just wipe the access led off with your finger.
I recommend you do this while your computer is off and the PSU in unplugged. Although, I had the computer on and CPUZ running and I did the Mod "live" and checked the VCore in CPUZ after each pencil stroke.Edited by Gunderman456 - 12/22/08 at 6:11pm