With the advent of the Intel(r) Pentium(r) III line, faster L2 cache was installed versus the equivalent clock speed P2 models, allowing for more leeway. This doesn't mean that it's all smooth sailing in P3 land, Intel(r) certainly doesn't make it easy for overclockers.

Thanks to the severe clock multiplier locks installed on all Intel(r) CPUs, users are forced to manipulate the Front Side Bus or FSB speeds of their mainboards to dictate higher CPU clock frequencies.

Here are some examples of clock multipliers for current P2 and P3 CPUs:

Possible P2-350 multiplier settings: 3.5 only
Possible P2-400 multiplier settings: 4.0 only
Possible P2-450 multiplier settings: 4.5 only
Possible P3-450 multiplier settings: 4.5 only
Possible P3-500 multiplier settings: 5.0 only
Possible P3-550 multiplier settings: 5.5 only
Possible P3-600 multiplier settings: 6.0 only

This effectively means that the P2 and P3s are literally 'frozen' at their respective speeds when they shipped. Luckily thanks to innovative mainboard manufacturers looking for a way to separate themselves from their own competition, the focus turned to manipulating the FSB speeds when overclocking CPUs.