E6750@3.00ghz overclock help

[Rail racer]

Hello everybody, I can not get my e6750 (2.66) to more than 3 MHz 8 * 375fsb (1500 in the bios). Has an nForce 650i SLI SPP chip (msi p6n SLI v2) under CPU-z running to 1.456 core voltage 0.1250 in bios. I have also NB and SB volts few steps, but I can not get the computer to boot unless it is just 3000mhz (1500 FSB in the bios, 1501 does not have tested 1510-1530)

I have something "ceiling"? Is there any way I can get some more MHz?

Sorry for the noob questions, am just beginning to overclock.

[SUpER CoP]

It is probably your chip that requires more Tweak. nForce chip is a nightmare from time to time.

[Rail racer]

OK, is there any guide how to 'Tweak' my chip? Have never done it
Any guide there for how to do.