Shamino over at VR-Zone's Forum has thrown up a Voltage modding Guide for the Athlon 64 boards ! Here's a rip.

Well, modding the Vcore of the Athlon 64 boards should be quite simple as most boards are using the ISL6559CB or ISL66569CB regulators.

Both the Shuttle and the Chaintech Nforce3 boards use the ISL6559CB and putting a VR between pin 10 and ground does the trick. Here are the positions of the chips on the boards.

Voltage modding the Athlon 64 boards