Comment by coldtea

3 years ago

>We know from theory that the physical limits to computation are high. So we could keep doubling for decades more before we hit some kind of fundamental physical limit, rather than an economic or political limit to Moore's Law.

Huh? Haven't we already hit close to the end of Moore's Law, and are compesating by adding cores (which is a different thing)?

And aren't we also pushing near the physical limits regarding the cpu nanometer race?

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coldtea

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fwlr  3 years ago

Few things have been tortured more than “Moore’s Law”, which originally meant an empirical observation that number of transistors on a single integrated chip of fixed size seemed to double every two years, but was broadly understood to mean “computation doubles every two years”, and as we found other ways to increase computation besides making smaller transistors we tended to gather those ways under the Moore’s law umbrella as well. Referencing Moore’s Law very rarely adds clarity, in my opinion. The cpu nanometer race is also similarly tortured: 3 nanometers might be close to the physical limit of semiconductor computation but that doesn’t mean anything, since “3nm” means 7 nanometer precision and a half-pitch length of ~14 nanometers. https://twitter.com/davidad/status/1661595361939533827

But enough nitpicking; the actual answer to your question is that those are about physical limits of our current hardware implementation of computation. The theoretical physical limits of computation that the author is thinking of are bounded by things like Margolus-Levitin’s limit of 6x10^33 operations per second per joule (I had to look up the SI prefix; it’s several thousand quettaflops). https://en.m.wikipedia.org/wiki/Margolus%E2%80%93Levitin_the...

  • coldtea  3 years ago

    >But enough nitpicking; the actual answer to your question is that those are about physical limits of our current hardware implementation of computation.

    Yeah, but unless we come up with another "hardware implementation of computation", which I don't see happening anytime soon, those are our limits for the next few decades at least, if not centuries (if not forever).

zamadatix  3 years ago

Moore's Law is about a relation of the number of transistors in a given cost chip, not just their size. Whether they have 1 core vs 4096 or whether the chip is 1 mm^2 vs1000 mm^2 doesn't really matter in terms of the law.

That said, I think the trend of transistor growth at a given cost has started to slow according to most graphs.

  • coldtea  3 years ago

    >Whether they have 1 core or 4096 doesn't really matter.

    It does however matter to the looser Moore's law expectations, which were about increased speed. Now this happens only for more parallelizable programs, as opposed to the automatic speed increase bumps programs got from Moore's law in the single-core eras...