Cooling the computer doesn’t let you get around the Landauer limit! The savings in energy you get by erasing bits at low temperature are offset by the energy you need to dissipate to keep your computer cold. (Erasing a bit at low temperature still generates some heat, and when you work out how much energy your refrigerator has to use to get rid of that heat, it turns out that you must dissipate the same amount as the Landauer limit says you’d have to if you just erased the bit at ambient temperatures.) To get real savings, you have to actually put your computer in an environment that is naturally colder. For example, if you could put a computer in deep space, that would work.
On the other hand, there might also be other good reasons to keep a computer cold, for example if you want to lower the voltage needed to represent a bit, then keeping your computer cold would plausibly help with that. It just won’t reduce your Landauer-limit-imposed power bill.
None of this is to say that I agree with the rest of Jacob’s analysis of thermodynamic efficiency, I believe he’s made a couple of shaky assumptions and one actual mistake. Since this is getting a lot of attention, I might write a post on it.
Deep space is a poor medium as the only energy dissipation there is radiation, which is slower than convection in Earth. Vacuums are typically used to insulate things (thermos).
Cooling the computer doesn’t let you get around the Landauer limit! The savings in energy you get by erasing bits at low temperature are offset by the energy you need to dissipate to keep your computer cold. (Erasing a bit at low temperature still generates some heat, and when you work out how much energy your refrigerator has to use to get rid of that heat, it turns out that you must dissipate the same amount as the Landauer limit says you’d have to if you just erased the bit at ambient temperatures.) To get real savings, you have to actually put your computer in an environment that is naturally colder. For example, if you could put a computer in deep space, that would work.
On the other hand, there might also be other good reasons to keep a computer cold, for example if you want to lower the voltage needed to represent a bit, then keeping your computer cold would plausibly help with that. It just won’t reduce your Landauer-limit-imposed power bill.
None of this is to say that I agree with the rest of Jacob’s analysis of thermodynamic efficiency, I believe he’s made a couple of shaky assumptions and one actual mistake. Since this is getting a lot of attention, I might write a post on it.
Deep space is a poor medium as the only energy dissipation there is radiation, which is slower than convection in Earth. Vacuums are typically used to insulate things (thermos).