[thrance]

Theoretically, a computer that never forgets anything can run without consuming any power (and thus never heating). That kind of computer would be called reversible (or adiabatic) as it would require its gates to be reversible (i.e. any computation can be undone). You would still need to expend energy to set the initial state (input) and copy the result (output).

Obviously, in real life, most power consumed by computers is lost by wire resistance, not through "forgetting" memory in logic gates. You would need superconducting wires and gates to build an actually reversible CPU.

Also, you would need to "uncompute" the result of a computation to bring back your reversible computer from its result back to its initial state, which may be problematic. Or you can expend energy to erase the state.

Quantum computers are reversible computers, if you seek a real life example. Quantum logic gates are reversible and can all be inverted.

[tamat]

Thanks for your explanation