Pentium IV 27.65 GHz CPU clock

[sniperviper21]

Not sure on world record for all processors, but the Pentium 4 world record is 7.1 Ghz by some Japanese dude. the Xbit page it was originally on is gone now though.

Dell also released a P4 gaming computer that ran at 4 Ghz.

the current world record 8.4Ghz
AMD Overclocks a CPU Past a World Record to 8.29GHz [Video] - Tested