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Why is it so hard to understand that "Moore's Law" is coming to an end - for silicon chips at least? The point of these stories is that we're getting to transi

by devx 13y ago

Why is it so hard to understand that "Moore's Law" is coming to an end - for silicon chips at least? The point of these stories is that we're getting to transistors being as big as atoms, and I think that's happening roughly around 2-3nm for silicon. Whether we'll still be able to improve performance for "computers", by switching to graphene transistors, which even if we can't shrink those anymore, we could maybe "optimize" and harvest all the performance from a graphene transistor. But that is probably going to keep us another 10 years or so. There aren't that many ways out - until we start making quantum computers, and hopefully silicon and graphene transistors will hold us until then.

mikeash 13y ago
It has to end at some point, certainly. But there's no particular reason to think it's now. Current technology for chips has been near the end since the 90s. So far, something has always come along to avoid the end.
- sharpneli 13y ago
  In a sense it has already happened. The clock speeds in production chips have not increased markedly in the last 10 or so years. Take a program that has lot of unpredictable branching, random memory accesses and heavily interdependent calculation (the next command always depends on the previous one) and you are not really much faster than old CPU's. The speedups in single core performance in recent years have mostly come from increasing bandwidth, automatically taking advantage of some concurrency (Out of order execution), more and more SIMD instructions etc etc. Interestingly enough if you want to write very high performance CPU code it's almost like writing OpenCL for GPU execution. I'd go so far to even claim that right now the best way to write high performance CPU code is to use Intel's OpenCL implementation for their CPU.
  - mikeash 13y ago
    Moore's Law was never about clock speeds. It was always about feature size i.e. number of transistors per square inch. For a long time, transistor count directly enabled higher clock speeds, and so people conflated the two. But the original statement of the Law has no mention of clock speeds. Why does it matter why single-core performance has continued to improve? It used to be clock speed, now it's something else, but it's still getting better all the time.
nivertech 13y ago
It's not transistors approaching the size of atoms, it's transistors' features.

by devx 13y ago

mikeash 13y ago

It has to end at some point, certainly. But there's no particular reason to think it's now. Current technology for chips has been near the end since the 90s. So far, something has always come along to avoid the end.

sharpneli 13y ago
In a sense it has already happened. The clock speeds in production chips have not increased markedly in the last 10 or so years. Take a program that has lot of unpredictable branching, random memory accesses and heavily interdependent calculation (the next command always depends on the previous one) and you are not really much faster than old CPU's. The speedups in single core performance in recent years have mostly come from increasing bandwidth, automatically taking advantage of some concurrency (Out of order execution), more and more SIMD instructions etc etc. Interestingly enough if you want to write very high performance CPU code it's almost like writing OpenCL for GPU execution. I'd go so far to even claim that right now the best way to write high performance CPU code is to use Intel's OpenCL implementation for their CPU.
- mikeash 13y ago
  Moore's Law was never about clock speeds. It was always about feature size i.e. number of transistors per square inch. For a long time, transistor count directly enabled higher clock speeds, and so people conflated the two. But the original statement of the Law has no mention of clock speeds. Why does it matter why single-core performance has continued to improve? It used to be clock speed, now it's something else, but it's still getting better all the time.

nivertech 13y ago

It's not transistors approaching the size of atoms, it's transistors' features.