14 ms·

> AMD should see the writing on the wall and start designing ARM CPUs. This is a really tough strategy decision. Focus all energy on delivering a knock-out blo

> AMD should see the writing on the wall and start designing ARM CPUs. This is a really tough strategy decision. Focus all energy on delivering a knock-out blow to Intel (in x86/64) or try to do other stuff too? For the next several years at least, there is still a whole lot of money to be made selling x86/64 chips. (I don't know if Microsoft has plans to move mainstream Windows users off x86/64, but even if they do, it won't happen quickly.) Right now, AMD has an opportunity to take x86/64 away from Intel. Probably the best opportunity in decades. There's something to be said for focusing all resources on delivering a knock-out blow right now, before the opportunity is gone. On the other hand, ARM might have a better future over the long term. And it isn't necessarily true that AMD would be spreading itself too thin by trying to do both.

foobarian 6y ago
I'm also curious if there is something inherent to ARM that would stop them from making similar optimizations to the AMD chips. They are already using TSMC so they are not held back by density.
- avianlyric 6y ago
  > I'm also curious if there is something inherent to ARM that would stop them from making similar optimizations to the AMD chips. Yeah ARM isn’t x86. Apple made big gains by leveraging the difference in instruction length and complexity between x86 and ARM. Something AMD can’t do, and they’ve said as much.
  - foobarian 6y ago
    I still don't have a clear understanding. Apple also made big gains by integrating performance sensitive stuff on the package. AMD could do the same. I wonder if they are constrained by some hardware-level interoperability requirements across the motherboard, like with chipsets or DMA controllers or whatnot made by different companies. Apple clearly has a nice advantage here.
    - omgwtfbyobbq 6y ago
      I think the performance sensitive stuff Apple integrated is to some extent dependent on their control of their own software stack, which AMD doesn't have control of.
    - kllrnohj 6y ago
      > Apple also made big gains by integrating performance sensitive stuff on the package. AMD could do the same. The only thing the M1 has integrated that a typical AMD or Intel laptop CPU doesn't have is a neural net processor. Everything else about the M1's 'integrated architecture' is typical. Notably the M1's RAM is not integrated as is often incorrectly stated. It's just regular soldered LPDDR4X. And M1's RAM latencies are worse than Intel & AMD's socketed DDR4 latencies, so being soldered and physically close is definitely not providing a performance advantage.
    - avianlyric 6y ago
      My understanding from reading around (I can't find sources right now) is that a big chunk of Apple's performance comes from how wide their instruction decode hardware, and long their instruction pipeline is. ARM instructions are fixed length so it's very easy to stack up decoders next to each other. You don't need complex logic to figure out where instruction boundaries are, which you do with x86. This added to a super long instruction pipeline means that the M1 has the ability to reorder a significant (something silly like 2x longer than any AMD or Intel CPU) number of instructions to increase CPU utilisation and thus performance. AMD can't do this on an x86 CPU because the complexity involved is too high, and think someone has found comments from them basically saying so. Yeah Apple did make gains from a better integrated package, some of that would be tricky to pull off else where without additional software support. Some of the other integrations would be tricky to pull of because it would reduce the amount of customisation OEM could do. Remember one of the big things Apple integrated was RAM, and making it unified memory for all the co-processors. That could be tricky to do, unless we move into a world where RAM is always integrated into CPUs.
elteto 6y ago
This is a very thoughtful comment, thank you. I would love to be a fly on the wall on the corresponding AMD strategy meetings :) I think to not focus on x86 right now would be a tremendous blunder on AMD’s part. And at the same time ignoring ARM for too long will give others (like Nvidia) time to setup shop and capture the market. I wonder how much of the Zen architectural “backend” is amenable to be reused with a different ISA (I don’t even know if such thing would be possible). Perhaps they could have a very low-effort initiative to try something along those lines.
klelatti 6y ago
For the moment I don't think its a tough decision at all - has to be x86 (and I say that as someone who has complained about the x86 duopoly). Why? - It's in both AMD and Intel's interests for x86 to remain dominant for as long as possible. If they could it would be in their interest to drive Arm new entrants out of the market (I don't believe that will happen though). - Introducing an Arm product (or even hinting at one) would add credibility to new entrants and undermine existing products. - They could almost certainly switch to an Arm design reasonably quickly if they needed to. There is also some uncertainty about the impact that Nvidia will have on Arm when it takes it over. x86 is AMD's jointly owned ISA - they have no control over the Arm ISA.

foobarian 6y ago

I'm also curious if there is something inherent to ARM that would stop them from making similar optimizations to the AMD chips. They are already using TSMC so they are not held back by density.

avianlyric 6y ago
> I'm also curious if there is something inherent to ARM that would stop them from making similar optimizations to the AMD chips. Yeah ARM isn’t x86. Apple made big gains by leveraging the difference in instruction length and complexity between x86 and ARM. Something AMD can’t do, and they’ve said as much.
- foobarian 6y ago
  I still don't have a clear understanding. Apple also made big gains by integrating performance sensitive stuff on the package. AMD could do the same. I wonder if they are constrained by some hardware-level interoperability requirements across the motherboard, like with chipsets or DMA controllers or whatnot made by different companies. Apple clearly has a nice advantage here.
  - omgwtfbyobbq 6y ago
    I think the performance sensitive stuff Apple integrated is to some extent dependent on their control of their own software stack, which AMD doesn't have control of.
  - kllrnohj 6y ago
    > Apple also made big gains by integrating performance sensitive stuff on the package. AMD could do the same. The only thing the M1 has integrated that a typical AMD or Intel laptop CPU doesn't have is a neural net processor. Everything else about the M1's 'integrated architecture' is typical. Notably the M1's RAM is not integrated as is often incorrectly stated. It's just regular soldered LPDDR4X. And M1's RAM latencies are worse than Intel & AMD's socketed DDR4 latencies, so being soldered and physically close is definitely not providing a performance advantage.
  - avianlyric 6y ago
    My understanding from reading around (I can't find sources right now) is that a big chunk of Apple's performance comes from how wide their instruction decode hardware, and long their instruction pipeline is. ARM instructions are fixed length so it's very easy to stack up decoders next to each other. You don't need complex logic to figure out where instruction boundaries are, which you do with x86. This added to a super long instruction pipeline means that the M1 has the ability to reorder a significant (something silly like 2x longer than any AMD or Intel CPU) number of instructions to increase CPU utilisation and thus performance. AMD can't do this on an x86 CPU because the complexity involved is too high, and think someone has found comments from them basically saying so. Yeah Apple did make gains from a better integrated package, some of that would be tricky to pull off else where without additional software support. Some of the other integrations would be tricky to pull of because it would reduce the amount of customisation OEM could do. Remember one of the big things Apple integrated was RAM, and making it unified memory for all the co-processors. That could be tricky to do, unless we move into a world where RAM is always integrated into CPUs.

elteto 6y ago

This is a very thoughtful comment, thank you. I would love to be a fly on the wall on the corresponding AMD strategy meetings :) I think to not focus on x86 right now would be a tremendous blunder on AMD’s part. And at the same time ignoring ARM for too long will give others (like Nvidia) time to setup shop and capture the market. I wonder how much of the Zen architectural “backend” is amenable to be reused with a different ISA (I don’t even know if such thing would be possible). Perhaps they could have a very low-effort initiative to try something along those lines.

klelatti 6y ago

For the moment I don't think its a tough decision at all - has to be x86 (and I say that as someone who has complained about the x86 duopoly). Why? - It's in both AMD and Intel's interests for x86 to remain dominant for as long as possible. If they could it would be in their interest to drive Arm new entrants out of the market (I don't believe that will happen though). - Introducing an Arm product (or even hinting at one) would add credibility to new entrants and undermine existing products. - They could almost certainly switch to an Arm design reasonably quickly if they needed to. There is also some uncertainty about the impact that Nvidia will have on Arm when it takes it over. x86 is AMD's jointly owned ISA - they have no control over the Arm ISA.