Reached the lowest possible voltages at 2.3GHz with an BE9600 now:

Vcore: 1.1625V
Vnbcore: 1.0625V
SB: 1.2V
NBcore: 1.12V
NBpcie: 1.12V
NBht: 1.03V

Beside the Sapphire Mobo and the BE9600 i used 2GB crucial ballistix 6400 tracers and HD2600XT gfx and an old U2W sata adapter with an 18GB 10000RPM IBM hd (lost too many sata hd's so i use old stuff for testing).

At stock voltages the system required ~220W AC under prim95 load. With optimized voltages it requires ~197W AC now. Also the cpu temp dropped ~3°C.

I did all this to make sure voltage limits will occure in early stages of overclocking. Guess it's saver to gain experiences with lower clock speeds and voltages.