Allright, X86, just to answer a few questions.
The i845E and it's ilk have a *maximum* supported frequency for operation of 133. Thus, you're 100MHZ FSB processor is well within spec.
Remarking on the P4 could only occur with the 1.6A and even then nobody would dare because intel is gonna phase those parts out soon. not all 1.6A's can run at 133 without a voltage bump. WindowsXP reads the microcode of the CPU and detects what kinda CPU it is and then tells it's overclocked speed, that'll circumvent all but the most persistent of remarkers.