Slightly unrelated but is there any way of maintaining that low of a temperature (77k and 10k according to the paper numbers) that does not immediately kill perf/w and perf/$ ?
Otherwise might as well just buy more cpu
>As IOFF at 77 and 10 K decreases by four to five orders [29], the primary constraint of building a large memory array, i.e., leakage current (Ileak), will not be a major concern and will lead to novel design tradeoffs for memory optimization.
This also gets rather tricky, because the standard way to connect computer chips is with copper traces, which are wildly good conductors of heat. A solution like this will probably need optical interconnects with the made from a thermal insulator.
It's a fun design problem to chew on
Leakage current is generally a rounding error for heat. In CMOS, the power that causes the most heat is the dynamic switching power which is lost to P = C * Vdd^2 * frequency
Which implies that for the fastest chips, most power is lost simply to running the clock which has both the highest frequency and largest capacitive load.
Where leakage current matters is for battery driven systems where you spend most of your time sleeping.
I strongly suggest that you go over this lecture "CMOS Power Consumption": https://course.ece.cmu.edu/~ece322/LECTURES/Lecture13/Lectur...
And if cooling it lets you shrink the SRAMs that’s also going to let you reduce the capacitance, so switching power will also be reduced. I’m sure a design optimised for low temp will do some clever stuff with clock hating as well.
The problem here is that you generally put SRAM on the same die, or at least package, as the processors. And those do switch many of their gates.
So you’d probably have to do this in a case where you want a lot of fast RAM in a different box, with some really fast optical interconnect to your processing cores.
Also, take a look at the Apple M3 chip, for example. Note how much of the die size isn't RAM.
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.
- 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.
OTOH, you might want to burry your supercomputer deep into the crust of Pluto (or in a permanently shaded lunar crater) with just a radiator sticking out.
Latencies between Earth and Pluto can be a problem for computing, but I would appreciate the impossibility of receiving Teams calls. Also, any AI running on that hardware will have a ton of time to think about... anything.