Others have answered why, here is the 'what would happen'. Heat your CPU up by pointing a hair dryer at it (you may want to treat this as a thought experiment a

Others have answered why, here is the 'what would happen'. Heat your CPU up by pointing a hair dryer at it (you may want to treat this as a thought experiment as you could destroy your computer). At some point it begins to fail because transistors are pushed past theiroperating conditions. Another way to push it to failure is to overclock. The results are ... variable. Sometimes you won't notice the problems, computations will just come out wrong. Sometimes the computer will blue screen or spontaneously reboot. And so on. Just depends where the failure occurs, and if the currently running software depends on that part of the chip. If a transistor responsible for instruction dispatch fails it's probably instant death. If a transistor responsible for helping in computing the least significant bit of a sin() computation, well, you may never notice it.