got some qn on Vcore.. help needed

i am trying to find lowest voltage possible for my stock 2.4GHz E6600. will there be a point where the voltage is 'too low' that i cannot boot? if so then what next? also, should i go from high volt and work downwards or set low and go upwards while testing for stability?

secondly, er.. how come when i run TAT my Vcore is 1.288v and normally it's 1.312v?? how come during load it becomes lower?

thx in advance

 

Yes. Then, if you cant access BIOS at all, you either clear/reset BIOS or use any physical switches on the board to reduce FSB(thereby reducing cpu clock speed which usually means it will run fine on a lot lower voltage) or override BIOS voltage settings.
If you can still get into BIOS, as many boards doesnt implement BIOS voltage settings until you have proceeded past the "BIOS stage", just set it higher again