Re: Long-term effects of overclocking. [continued from CM9 thread
Processors are binned.
They take it and run a test, if it's completely stable at max speed, they mark it at max speed. If it's less, they try the next step down, if it's stable it gets marked there. They continue this until they get to the slowest speed offered for that particular model or dispose of it. If they don't have enough slower ones, they can grab some from the other, faster binned chips. This is why overclocking works, you get lucky and have one that was pulled from a higher bin. However, you never know if you did or not, and you also don't know why yours may have been binned down in the first place.
What happens a lot is the manufacturer binned it because maybe it was stable at 768, but not quite 806. You on the other hand don't have their ability to test as precise and think you are stable at 806 and yet you aren't. If the processor has a week spot, you can burn up some of the transistors and lose speed, others that are okay, may start strong and weaken over time. The factories know this. They can test for it, and plan ahead for it, it;s not a big deal if over time you drop a few, but with overclocking (which uses more power and generates more heat), you can start dropping them fast.
The smarter computer overclockers realize it's hard on the chips, but they take steps to minimize the damage by using more powerful coolers and understanding that they are shortening the lifespan of the processor. The goal is to make sure it lasts long enough until your next upgrade. On phones, we don't have the luxury of better cooling and rarely the option of undervolting (which can help or hurt).
It's all a big game, if you want to play, be prepared to lose on occasion.
I know a ton of people who have burned up A LOT of components overclocking.