Here are the Palit 8800GT non-reference voltage mods and measure points
(developed by Nick Rimer and tested by Droperidolum (i.e. me ) from Overclockers.ru):

Please note before making this mod that you need to improove coling, especially on mosfet and coils, cause on 1.25V-1.30V it becomes very hot!
Some photos and default/overclock@1.36V/2.10V results screens you can find here (in Russian).
This mod also suitable to some XpertVision, Gainward and MSI non-reference cards based on this PCB design.
Good luck!