Calibrating Core Temperature

[The Doc]

I'm following a procedure to calibrate RealTemp/SpeedFan which requires dropping my E6750 CPU frequency below stock speed (2.66Ghz) and voltages to reduce CPU idle power consumption to minimum. I'm trying to drop my CPU speed down to 1.6Ghz (200FSB x 8 multiplier). However, the BIOS appears to be preventing me from doing so - If I attempt to set a speed below the stock clock speed of 333MHz, then on re-boot it resets it back to 333 x 8 (1333 FSB/2.66Ghz CPU). Am I missing something here, or is my Mobo stopping it?

 

[ilovebarny]

why do you want to calibrate your realtemp/speedfan?? is it supposed to make it work better?? on my mobo(bfg 680i with intel e6750) i get precise temps with speedfan. (i dont use realtemp. i use coretemp)

 

[The Doc]

The reason I want to calibrate is outlined here: http://www.techpowerup.com/realtemp/docs.php. Basically The author claims that Coretemp and Speedfan are inaccurate (I get a 5C difference between them and Realtemp).