first, get a really nice stopwatch, then turn on your pc, as soon as your Duron takes off, start the stopwatch, let it complete 3 laps as this is a good distance, halfway between an endurance run and a sprint.
anything under 2 minutes, you might want to think about trying out for the Olympics, I hope you are American though cause they could use you.
Seriously, can you be more specific, do you mean overclock or what in the heck are you asking?