When considering any type of overclocking, we like to remind readers that overclocking will void the warranty of your components. While companies promote products that are designed to overclock - such as Intel's Core 2 Extreme processors - any claims that it was designed for modification are accompanied by disclaimers telling you that you will void your warranty if you modify them beyond specifications.
Right on Intel's website you can read this: "Plus, the Intel Core 2 Extreme processor locks (overspeed protection) have been removed so you can mod and overclock your PC beyond the extreme.1" Unlocking the clock multipliers so owners can experiment with overclocking is one selling feature of the processor.
As an intelligent consumer, though, you need to check the fine print. The 24 word comment on cool and exciting adjustable speeds is accompanied by the notation marked by a superscripted 1. That disclaimer has twice as many words and concludes by stating that Intel does not warranty anything pushed beyond spec.
"¹ Altering clock frequency and/or voltage may (i) reduce system stability and useful life of the system and processor; (ii) cause the processor and other system components to fail; (iii) cause reduction in system performance; (iv) cause additional damage; and (v) affect system data integrity. Intel has not tested, and does not warranty the operation of the processor beyond its specifications."
These two statements underscore the two major philosophies at work here. The first is that companies genuinely want to stand behind their products; the second is that there are risks inherent in pushing hardware past its design limitations. These two issues don't mesh well for 99% of the companies out there. If you take a Ginsu knife and abuse it, they will replace it, but when you are talking about delicate semiconductors, replacing a component is a much more expensive proposition.
One main concern with overclocking is the possibility of destroying the components you are going to be stressing. Semiconductor companies have extensive quality assurance measures in place to make sure products leave the factory in good working order. Manufacturers do not want to have their product come back to them under warranty; it cost money to fix or replace defective parts. Maintaining warranties for appropriately used products is required to keep customer confidence high and hopefully result in repeat business. However, companies do not want to replace intentionally altered components.
That said, if we are going to void our warranties, then we should to talk about risks involved and how to minimize them.