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Comment by sliken | Hacker News Reader

Can't imagine why it would, but the lack of heat makes a 3D cpu much more feasible. So you could take 20 die, make 20 layers, and get radically more transistors per volume.

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Seems like it would be much harder to keep a stacked CPU superconducting as heat dissipation would be more difficult.

Maybe I'm misunderstanding but since this 3D CPU would be superconducting, it would conduct electricity without resistance and therefore not generate any heat while in use.

The adiabatic (reversible) computations themselves would be zero-loss, but in order to actually read the result of your computation you need to waste heat.

Maybe there are parts which are not superconducting? Like impurities in the material. So even though the generated heat is like 0.01% of the original, some heat is still generated.

If you went a bit colder you could use superfluid helium and laser cut microchannels through the whole die. You would need to cool it to 2K and every degree at that temp is a fight but once past the transition point it becomes a remarkable thermal conductor and loses all viscosity. It seeps through tiny pores in porcelain like it's a sponge.

Solid idea, but the same thing that makes it work is what makes it impractical. Helium is almost impossible to contain long term, and would have to be replenished regularly.

Presumably 80x less power including cooling means more than 80x less power not including cooling.

I'd think that should be enough to get quite a few layers, sure maybe some minimal space between layers for cooling, but radically less than the non-superconducting designs.

Could a design with gaps between layers, but still connected as one not mitigate that though?.

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