I've got a contender:

A PIII-1000Mhz processor o/c'd to 1.1 Ghz.

It's stuffed in a Compaq Deskpro Micro-atx case if you can believe it.

Sandra 2001 CPU benchmark scores:

ALU - 2941
FPU - 1464

I thought this looked pretty good compared to the (lower) P4 1.5 scores in the benchmark comparison.

Has anyone else bumped up a P3 to P4 killing levels?

T