[Dylan16807]

Phase change yes. Or water chillers.

I can't imagine why anyone would be more inclined to use a peltier as wattage increases. Higher wattages make that idea progressively worse unless you have some very specific and strange requirements.

[hinkley]

Are you talking about the giant Peltiers that flopped in the late 90's and early 00's? Nobody is talking about that. I'm talking about micron, maybe millimeter-scale peltiers to increase the thermal conductivity of the absolute worst spots on the chip. That may mean a particular ALU, or it could mean circuits with far more layers than we can manage now (due to yields and thermal limitations)

[Dylan16807]

> the absolute worst spots on the chip. That may mean a particular ALU

The worst spots aren't much worse than the median spots (over calculating silicon, not cache). Anything big enough to be a hot spot, like a big ALU, is big enough to represent a large portion of your power budget. The main goal is to get all the heat away from the chip, and putting peltiers on a large portion of the chip gives you more heat to take away. For anything significantly smaller than that, the heat bleeds out without the need of a peltier. There might be a middle ground where peltiers could make a real life difference, but I'm skeptical.

> or it could mean circuits with far more layers than we can manage now

That sounds like you're cooling the entire chip, which is the worst time to use a peltier.