Geforce 8800GTS 320MB Pencil Voltage Mods
 

These cheaper G80 based video cards are quite the overclockers, you can push them even further by upping the voltage without touching a soldering iron:

"You can pencil the resistor marked above carefully to increase GPU Memory Voltage, or for better precision, you can solder a 20K ohms Variable Resistor to the spot marked and hook the other leg to any grounded spot. Set VR at Maximum Resistance and tune down resistance to increase voltage. Original resistance of resistor is 538ohms, reducing resistance by 10ohms will increase voltage by 0.05v.

http://www.vr-zone.com/?i=4641