From HowToGeek
The QuestionThis is a hypothetical question about how a CPU operates. If I purchase two identical CPUs, and use one long term (say one year), will it be identical in speed to the unused CPU? Will the number of clock cycles, latency of requests, etc on the used CPU be less than that of the unused CPU?
A supporting argument may be that mechanical devices degrade over time, While a CPU has no moving parts (other than the external fan), it does have circuits that can be damaged by heat, and voltage spikes. Lets say that after a year of intensive use, the circuits degrade and fewer electrons can pass since the pathway is narrower, etc.
Is this the nature of how a CPU operates, or is it simply working or broken, with no speed degradation in between?
The Answers ??
http://www.howtogeek.com/130355/is-cpu-performance-affected-by-age/