I remember OCing for the very first time with a Celeron 300. The processor was inexpensive compared to Pentium processors of the same vintage (its weakness was a very small L2 Cache). It came on a rather large supporting card (hope this isn't ancient history for everyone) with four solder traces that had to be interrupted in order to run the thing at 450 Mhz. IIRC. Most people covered the "pins" so that they couldn't contact their opposite numbers in the CPU's slot on the mainboard.
The danger of doing this was that if any one of the four solder "pins" contacted the juice it was supposed to get (when running normally) poof, dead processor.
I decided to get serious, I bought a magnifying visor and some needle files. Then I cut through the solder traces that led to the "pins," actually gold coated "fingers" on the bottom of the circuit board that the Celeron was mounted on.
Excellent, permanent overclocking, no chance of blue smoke!
Can't remember if this was before or after code name "Sledgehammer." I'm lucky to be able to buy a new CPU every five years or so. Truth be to tell, I don't really need the processing power I have in my latest box. But that guy Daniel~ insists on an i7, so is my i5 THAT much of a sin? I wish AMD made better processors and Intel made lousier ones.