It’s pretty much just simple energy loss that causes heat build-up in electronics. That ostensibly innocuous warming up, though, causes a two-fold problem:
Firstly, the loss of energy, manifested as heat, reduces the machine’s computational power — much of the purposefully created and needed, high-power energy disappears into thin air instead of crunching numbers. And secondly, as data center managers know, to add insult to injury, it costs money to cool all that waste heat.
For both of those reasons (and some others, such as ecologically related ones, and equipment longevity—the tech breaks down with temperature), there’s an increasing effort underway to build computers in such a way that heat is eliminated — completely. Transistors, superconductors, and chip design are three areas where major conceptual breakthroughs were announced in 2018. They’re significant developments, and consequently it might not be too long before we see the ultimate in efficiency: the cold-running computer.