GeForce 8800 GS/GT/GTS Voltmods
Memory Voltage Mod''
Locate the chip labeled "6549CBZ" on the backside of the card. For this modification use a 20 kΩ variable resistor. Prepare the VR as described earlier. Solder the wires on legs #4 and #7 as per the instructive picture above.
Monitor the resulting voltage with your multimeter: Red probe to the point marked with a green arrow labeled as "vMEM" (see paragraph: Overview), black probe into a ground.