Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

New superconductor microprocessor yields a substantial boost in efficiency

spectrum.ieee.org

Post reply on HN
Print view View original

161–170 of 233 posts

Re: New superconductor microprocessor yields a substantial boost in efficiency

#161

Post by 6nf »

bananabreakfast wrote: post #132
TheRealNGenius wrote: post #123

Earlier quoted context omitted.

No need to assume when we can define ;p

I think they were alluding to the fact that it is impossible to measure the one-way speed of light, and even the definition is an assumption based on the two-way speed

Since the one-way speed is impossible to measure can we just define it to be half of the two-way speed? There's no way to tell if that's correct or not but it makes no difference in any measurements you could make. So maybe for convenience we can just choose the one-way speed to be half the two way speed to simplify the calculations.

Re: New superconductor microprocessor yields a substantial boost in efficiency

#162

Post by 6nf »

centimeter wrote: post #156
the8472 wrote: post #18

> We use a logic primitive called the adiabatic quantum-flux-parametron (AQFP), which has a switching energy of 1.4 zJ per JJ when driven by a four-phase 5-GHz sinusoidal ac-clockat 4.2 K. The landauer limit at 4.2K is 4.019×10^-23 J (joules). So this is only a factor of 38x away from the landauer limit.

> The landauer limit at 4.2K is 4.019×10^-23 J (joules). At room temperature.

Hmm that's interesting. At lower temperatures, would the limit also be lower? Or what's the relationship between temp and Landauer?

Re: New superconductor microprocessor yields a substantial boost in efficiency

#163

Post by MertsA »

fastball wrote: post #51
sliken wrote: post #28

Earlier quoted context omitted.

Can't imagine why it would, but the lack of heat makes a 3D cpu much more feasible. So you could take 20 die, make 20 layers, and get radically more transistors per volume.

Seems like it would be much harder to keep a stacked CPU superconducting as heat dissipation would be more difficult.

If you went a bit colder you could use superfluid helium and laser cut microchannels through the whole die. You would need to cool it to 2K and every degree at that temp is a fight but once past the transition point it becomes a remarkable thermal conductor and loses all viscosity. It seeps through tiny pores in porcelain like it's a sponge.

Re: New superconductor microprocessor yields a substantial boost in efficiency

#164

Post by nicoburns »

centimeter wrote: post #156
the8472 wrote: post #18

> We use a logic primitive called the adiabatic quantum-flux-parametron (AQFP), which has a switching energy of 1.4 zJ per JJ when driven by a four-phase 5-GHz sinusoidal ac-clockat 4.2 K. The landauer limit at 4.2K is 4.019×10^-23 J (joules). So this is only a factor of 38x away from the landauer limit.

> The landauer limit at 4.2K is 4.019×10^-23 J (joules). At room temperature.

What does the 4.2K mean then? I assumed that was the temperature in kelvin.

Re: New superconductor microprocessor yields a substantial boost in efficiency

#165

Post by nicoburns »

root-z wrote: post #78
akiselev wrote: post #71

Earlier quoted context omitted.

Is that the case for our highly centralized clouds? No one's putting a liquid nitrogen cooled desktop in their office so this type of hardware would be owned by companies who are financially incentivized to drive down the overhead costs of commoditized functionality like networking, data replication and storage, etc. leaving just inefficient developer logic which I assume is high value enough to justify it.

It's quite common in the cloud industry to trade hardware for shorter development cycle these days too. I think that's because there is still very high growth in the sector and companies all want to be the first offering feature X. As cloud services become more mature I expect people will be more cost sensitive. Though when that will happen I cannot say.

I think it's largely because deceloper time is so expensive. Hardware seems cheap in comparison in many contexts.

Re: New superconductor microprocessor yields a substantial boost in efficiency

#166

Post by joshspankit »

yazaddaruvala wrote: post #118
ajuc wrote: post #105

Earlier quoted context omitted.

> IMO, The fact that it's only 38x the minimum is MIND BLOWING. It's like if someone made a car that drives at 1/38th the light speed.

For anyone too lazy to math, its a car that can go: 28.4 million km per hour (i.e. 17.6 million miles per hour) I wonder how much that speeding ticket would cost. Disclaimer: Assuming the one-way speed of light is 300k km/s

There are some places where the cost of the ticket goes up the higher you are above the limit. Assuming it’s a school zone in one of those areas (pick whichever one you can answer for), what would the cost be then for going 28.4 mkm/hr?

Re: New superconductor microprocessor yields a substantial boost in efficiency

#167

Post by nicoburns »

jessriedel wrote: post #76
Calloutman wrote: post #46

Earlier quoted context omitted.

Not really. You just have the whole package instead a vacuum casing.

Really. Vacuum casing is not even close to sufficient to set heat absorption to zero because of thermal radiation. And you can't just make the walls reflective once the cold object gets smaller than the wavelength of the radiation. The colder the object, the longer that wavelength.

What kind of wavelengths are we looking at for the kind of temperatures used in this article?

Re: New superconductor microprocessor yields a substantial boost in efficiency

#168

Post by nicoburns »

AnIdiotOnTheNet wrote: post #43
layoutIfNeeded wrote: post #14

Earlier quoted context omitted.

>Imagine how programming and operating systems might look in a world where processing power is 80x cheaper. So like 2009 compared to 2021? Based on that, I'd say even more inefficient webshit.

Considering that many modern interfaces are somehow less responsive than ones written over 20 years ago even when running those programs on period hardware , I feel certain that you are right.

Some things have improved a lot. Remember how long it took to boot a 2009 PC. I suspect if hardware perfromance stagnates then software optimisation will develop again.

Re: New superconductor microprocessor yields a substantial boost in efficiency

#169

Post by delecti »

joshspankit wrote: post #166
yazaddaruvala wrote: post #118

Earlier quoted context omitted.

For anyone too lazy to math, its a car that can go: 28.4 million km per hour (i.e. 17.6 million miles per hour) I wonder how much that speeding ticket would cost. Disclaimer: Assuming the one-way speed of light is 300k km/s

There are some places where the cost of the ticket goes up the higher you are above the limit. Assuming it’s a school zone in one of those areas (pick whichever one you can answer for), what would the cost be then for going 28.4 mkm/hr?

Fortunately you could quickly get to a jurisdiction that didn't extradite.

Re: New superconductor microprocessor yields a substantial boost in efficiency

#170

Post by marcosdumay »

6nf wrote: post #162
centimeter wrote: post #156

Earlier quoted context omitted.

> The landauer limit at 4.2K is 4.019×10^-23 J (joules). At room temperature.

Hmm that's interesting. At lower temperatures, would the limit also be lower? Or what's the relationship between temp and Landauer?

It's linear, so there's an almost 100 times decrease.
Post reply on HN