Temperatures have a direct correlation with resistance in a CPU (Positive temperature co-efficient). Which mainly affects a few things to my knowledge:
- Voltage requirement
- Degradation (via Current Crowding)
- CPU overclocking (as a result of the first one).
For example at ambient room temp with water my 3570K will do 5GHz @ 1.34V, at -25c it does 5.45 at the same voltage and 5.7 at -50c.
But a CPU at 4.5GHz at -80c and a CPU at 4.5GHz at 80c will perform the same (provided its the same CPU), one will just require less volts.
Anandtech did a bit on degradation a while ago, although it was applying to the 45nm Hi-K MG used at the time the principle is still the same.
I know someone whos G3258 was folding for about 2 years and it went from 4.6 1.22V to like 4.4 1.27V.