I have an HP nc6000 with a 1.7ghz Pentium M. The chipset is 855pm. I have found a Pentium M 2.5ghz pulled from an 852pm chipset. The 852 runs 533fsb when it is not on battery but 400 when on battery. the 855 runs 400 I believe at all times. The price and increase in fsb for the 2.5 is tempting and I would like to know if anyone can tell me if they are compatible? Even a link to a compatibility site would be appreciated. thanks Keith