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kickopotomus | 2 years ago

Superconductors may reduce power consumption but they don't do anything to improve transistor density.

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spaethnl|2 years ago

Before the node-size race we also had the clock-speed race. Eventually it was common for processors reach 2-4ghz, and after that the clock speed gains stopped being practical because as you increase clock speed you also increase energy requirements and heat.

I think the implication is that clock-speed could start increasing again. It would probably require a completely new manufacturing process, but if we assume this superconductor is legit, perhaps an older process could manufacture it.

If so, maybe we could have (just spitballing here, I have no idea) 28nm super conducting CPUs that run at a 1thz instead of 4ghz. That would be quite an improvement over today's CPUs, even with fewer transistors, I think.

There are other losses and limitation in increasing clock-speeds aside from just resistive losses, but I think they are a significant part of the current bottleneck. Other losses involve transistor switching losses, and inductive losses but I don't really know the details, and I think those details change with superconductors.

kickopotomus|2 years ago

We stopped chasing clock speeds because of the physical timing limitations of gate and signal propagation. Not because of heat. Suppose you are using a 5GHz clock. Every cycle is 0.2ns. Light can only travel 6cm in that time. Electricity propagates a little slower through a conductor (and even slower through silicon). So if you are using some insanely fast clock, you are just wasting cycles waiting for signals to move across the chip.