My opinion on this matter, and juft for the record I'm a authorised "Intel Product Integrator" so I do have a certain amount of perspective on this subject.
Intel manufacture a single product range, beit Pentium's, Pentium II's or Pentium III's, etc.
These come off the line, and are then tested at the highest rating possible. If they pass, they are rated at that speed. If they fail, they go to the next rating test down, etc. until it passes.
Over-Clocking is guaranteed to reduce your processor's MTBF and will inevitably have you claiming foul to your supplier. You may not like the results.
Taking it into an aviation perspective, I for one, wouldn't be happy if an engineer hadn't done the maintenance he should and stated "the manufacturer want us to change this part so they can make more money. There's no harm in leaving it there for say another 1000 hours".
Safety is the aviation industries #1 concern, reliability ( or MTBF ) is the computer industries.
Don't clock your processor, it will fail.
Whooaahh!!!