You can use this form to see how high people were able to overclock their
processors, so you'll have some idea of how high you will probably be able
to overclock yours.
Remember, however, that overclocking is an inexact science at best, and
sheer dumb luck at worst. To maximize your chances of a successful
overclock, be sure to use a humongous heatsink and fan along with thermal
grease. Keep your CPU as cool as possible!