Grab the latest version of CPU-Z if you haven't already! Recently version 1.27 was launched and is worth the update if you need it. This update supports Pentium 4 6xx processors and has a new validation system built in.

"CPU-Z is a diagnostic tool that provides information on your CPU, including: processor name and vendor, core stepping and process, processor package, internal and external clocks, clock multiplier, partial overclock detection, processor features, supported instructions sets, L1 and L2 cache information, location, size, speed, and technology."