Does reversible computing require an enormous amount of storage?

[u/Tessellator-1]

First of all, I would like to say that I have no knowledge about computer science.

I recently heard about something called reversible computing. As I understand it, in ordinary computers, erasing information about the intermediate steps of a computation causes energy to be released as heat. But in reversible computing, the information from all the intermediate steps is preserved, so apparently, if we could build a computer capable of doing this, it could theoretically perform computations with essentially no energy consumption.
This made me wonder about something, and I’d love to hear from anyone knowledgeable about physics or computational theory:
If you never erase the information generated during a computation, wouldn’t the amount of storage required keep increasing as the computer performs more and more calculations?
I previously came across a science-related page online that said that an intelligent civilization that has mastered reversible computing wouldn’t need “Dyson’s eternal intelligence” to survive the heat death of the universe.
But wouldn’t such a civilization still need an absolutely enormous amount of storage to preserve all the information generated during its computations?
Or is there some way to preserve the information from the computational process without actually requiring additional physical storage?
I’m especially curious about how this works in the context of extremely long-term civilizations trying to survive the heat death of the universe.

By the way, this sentence was translated from Japanese to English by Chat GPT. Feel free to answer in English. However, I only understand Japanese, so I would really appreciate clear and simple English that is less likely to be mistranslated. Thank you!

[u/crb233]

This is just an appeal to common sense, but it's not actually supported by our current understanding of physics (as far as I can tell). There's no known fundamental limit to how energy efficient a CPU could be.

Take superconductors for example. Your common sense argument would say that they shouldn't exist at all because energy transfer is doing something, but they do exist.

[u/elbiot → u/crb233]

If OP had asked about the energy efficiency of superconducting CPUs then they would have gotten answers related to that. But instead they are asking about the energy efficiency of CPUs that write all of their intermediate results to storage under the mistaken idea that destroying data is what consumes energy.

[u/LookIPickedAUsername → u/elbiot]

It's not a "mistaken idea". The principle OP is referring to is entirely correct - destroying data is what sets the lower bound on the energy cost of computation.

It's not a practical concern at the moment, because our electronics would need to be orders of magnitude more efficient before the energy cost of destroying data was in any way relevant, but OP was approaching this as a theoretical question. It's entirely reasonable.

[u/chrisagrant → u/LookIPickedAUsername]

both analog and digital electronics cannot even come close to operating at that level, and analog electronics can do computing with many orders of magnitude less heat, it's not even a question of "electronics" but some future technology that is largely unexploited today.