My Circuit Theory I professor told us that as heat increases, conductors raise in resistance. Which of course is true. He also said however, that semiconductors raise in resistance as they get colder. Now at first I thought maybe he slipped, because he does that sometimes. But he used that example in other lectures as well...If this is true, how is it that supercooled microprocessors (phase change for example) run so much faster than with air cooling? Is this guy an idiot or is there something I am missing here?