ASRock 939Dual-SATA2 VCore & VDimm Voltmods
ST Microelectronics' L6711 voltage controller can deliver up to 1.550V to the CPU. The output voltage is selected via VID code. For example if the VID code is 00110, the resulting voltage is 1.400V.
The marked solder pads have the "signal" on the left and ground on the right. So if you bridge one of these, the VID code will always be 0, no matter what the CPU sets.
The following table lists all possible VID code combinations.
For this mod we will change the VID4 code to always return '0'. This is done by bridging the VID4 solder pads with a solder blob or conductive paint.
Now, if the BIOS sets a voltage of 1.100V (VID Code 10010), the resulting VID code would be 00010, which is 1.500V.
With the voltmod done, any voltages listed in the table above that have a 1 for VID4 will get a 0.4V bump. The list in the BIOS will be the same, but the actual voltage is different.
So if you set 1.150V in the BIOS the real output voltage will be 1.550V, if you set 1.125V it's 1.525V, 1.100V is 1.500V an so on.
Voltages which already have a 0 for VID4 remain unaffected.