1. Most of the time it works. 2. If you get it wrong, you really screw up. 3. Screw ups are bad. Screw ups like blowing your $200 Motherboard. First thing, don't ever try to push your processor to insane speeds without proper cooling. A P2 400 should not go to 800. A 200% increase is virtual suicide - your processor would, on average, be running at 150 Degrees Celscius. Your computer won't get past the loading of you OS. After you've blown your motherboard, start weeping like a girl. Overclocking can be lethal,
Not like a gun is lethal, but like a brick wall along a highway is lethal.
  - Douglas Adams, The hitch hiker's gude to the galaxy.