[short_sells_poo]

77k is basically the boiling point of liquid nitrogen, and 10k is probably the same for liquid helium. Liquid nitrogen is in ample supply and is not difficult to manufacture, I suppose one could have a facility on site to produce it and use it immediately. It is going to be very energy intensive though... to answer your question, I struggle to think of a scenario where it would be better than buying more compute power. I suppose for stubbornly serial workloads... but I'm not sure what that could be? Running Crysis at 20k resolution?

[pfdietz]

Boiling point of He at 1 bar is 4.222 K, and its critical point is at 5.1953 K. At 10 K helium is a gas.

[short_sells_poo]

Ah thank you! I'm surprised they'd pick an odd temp like 10k then. I had a vague memory of this being close to the He boiling point but couldn't remember how tight the margins were.

[XorNot]

You can make liquid N2, though very inefficiently. So yeah, power is an issue although we are still making gains on cooling efficiency so it's not inconceivable the equation could swing towards super low temperature coolants.

[zmgsabst]

I was curious, so I googled around a bit — please excuse the weird units.

- about 0.375kWh to produce 1kg of LN2

- about 0.056kWh to boil 1kg of LN2

So you get 15% efficiency; though you have “waste cold” in the exhaust you could recover if you wanted, eg, to run a Sterling engine. You still have a 220K temperature differential after boiling to gas versus ambient.

[asdfadsfgfdda]

One slight advantage: you can store liquid nitrogen. So, you can use cheaper electricity to produce it

[changoplatanero]

The idea I heard was to make liquid nitrogen during the day when solar power is abundant and then run the chips at greater efficiency at night using your stored liquid nitrogen.

[Tostino]

Trading algorithms.

[short_sells_poo]

Right - very good point! But this is really only relevant for HFT algos, almost everything else is much less sensitive to speed and is also more parallelizable.

For HFT to work, it needs to be colocated I believe, and I haven't heard of anyone trucking in liquid N2 or producing it on premises though. Not saying it isn't happening, I'm involved in mid freq trading so I only have circumstantial knowledge.