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Is ARM's power advantage really that significant for devices larger than the smart phone / tablet form factor? If an Atom-based CPU consumes ~2-3 extra watts bu

by neilc 16y ago

Is ARM's power advantage really that significant for devices larger than the smart phone / tablet form factor? If an Atom-based CPU consumes ~2-3 extra watts but offers marginally better performance and (more importantly) compatibility with an enormous base of existing applications, that doesn't seem like a very compelling argument for switching.

sanswork 16y ago
Think of a data center situation though where you can get a ~50% power requirement difference for marginal performance decreases. The cost savings would be huge even if you require more servers to make up for the performance difference. For most home users I think you're right for now but for businesses it could be huge.
- pjscott 16y ago
  Of course, you've got to remember that which chip has the best performance per watt depends on the job. A sufficiently smart data center could determine this automatically and take that into account in its job scheduling.
- anamax 16y ago
  > Think of a data center situation though where you can get a ~50% power requirement difference for marginal performance decreases. 50% lower processor power isn't the same as 50% less system power.
hackermom 16y ago
Except that the Atoms at same (and even a bit higher) clock don't even offer marginally better performance. And another thing that I came to think of that weighs heavily in ARM's favor is the multitude of composite, multifunctional chips, SoCs etc. currently available in the ARM flavor. Is there ANYTHING like this for Atom, or any x86 at all?
- maximilianburke 16y ago
  Yes, AMD's Fusion line (http://en.wikipedia.org/wiki/AMD_Fusion http://en.wikipedia.org/wiki/AMD_Fusion) aims to provide SoC functionality.
- nl 16y ago
  Except that the Atoms at same (and even a bit higher) clock don't even offer marginally better performance. Depends if we are talking Arm Cortex-A8 or Cortex-A9. Atom is much more powerful at same clock speed that Cortex-A8. Cortex-A9 is getting closer competitive, but doesn't have much of a power advantage over it. (Lies, damn lies and benchmarks, but A8 gets ~2000 MIPS, A9 ~2500 MIPS and singlecore 1st gen Atom gets ~3300 MIPS) Also, multicore-Atom has been in the market for a while. Multicore ARM is just coming online now. It's worth noting that Intel can speed up Atom whenever they want. There are plenty of easy wins in there (eg, better execution core, faster memory controller) that they can put in if they need to keep their lead.
  - ssp 16y ago
    (Lies, damn lies and benchmarks, but A8 gets ~2000 MIPS, A9 ~2500 MIPS and singlecore 1st gen Atom gets ~3300 MIPS) Measured how, and at what frequencies? Also ARMs are really starved for bandwidth. Has that improved with the Cortex A9?
pkaler 16y ago
Is ARM's power advantage really that significant for devices larger than the smart phone / tablet form factor? I'll bet $5 that the MacBook Air in the future (18-24 months) will switch to ARM once the >2GHz ARM processors start shipping en masse. The Asus Eee PCs running Android with Snapdragon processors already embed the Cortex-A9 MPCores.
- jbarham 16y ago
  "4GB RAM ought to be enough for anybody." ARMS's Achilles' heel is that it's only 32-bit, and I don't think anyone wants to go back to a segmented address space any time soon.
  - jbrennan 16y ago
    That's a great point. Are there any 64 bit ARM chips on the horizon? I don't know much about chips, so maybe it's not even possible given the architecture.
    - 1amzave 16y ago
      I don't recall hearing any announced, though I wouldn't be surprised at all if it were currently in the works. The A15 mentioned in the article, however, I believe has something in the spirit of x86's PAE that offers an expanded (36 bits or so?) physical address space, for better or for worse (better in that you can address more memory, worse in that it's kind of an ugly hack and not a great long-term solution).
    - ryanpetrich 16y ago
      It's possible, but just like the x86-64 transition it won't be pretty.
      - protomyth 16y ago
        It might go better for ARM given that most of the more tightly controlled software that is delivered on ARMs (app store or custom embedded).

by neilc 16y ago

sanswork 16y ago

Think of a data center situation though where you can get a ~50% power requirement difference for marginal performance decreases. The cost savings would be huge even if you require more servers to make up for the performance difference. For most home users I think you're right for now but for businesses it could be huge.

pjscott 16y ago
Of course, you've got to remember that which chip has the best performance per watt depends on the job. A sufficiently smart data center could determine this automatically and take that into account in its job scheduling.
anamax 16y ago
> Think of a data center situation though where you can get a ~50% power requirement difference for marginal performance decreases. 50% lower processor power isn't the same as 50% less system power.

hackermom 16y ago

Except that the Atoms at same (and even a bit higher) clock don't even offer marginally better performance. And another thing that I came to think of that weighs heavily in ARM's favor is the multitude of composite, multifunctional chips, SoCs etc. currently available in the ARM flavor. Is there ANYTHING like this for Atom, or any x86 at all?

maximilianburke 16y ago
Yes, AMD's Fusion line (http://en.wikipedia.org/wiki/AMD_Fusion http://en.wikipedia.org/wiki/AMD_Fusion) aims to provide SoC functionality.
nl 16y ago
Except that the Atoms at same (and even a bit higher) clock don't even offer marginally better performance. Depends if we are talking Arm Cortex-A8 or Cortex-A9. Atom is much more powerful at same clock speed that Cortex-A8. Cortex-A9 is getting closer competitive, but doesn't have much of a power advantage over it. (Lies, damn lies and benchmarks, but A8 gets ~2000 MIPS, A9 ~2500 MIPS and singlecore 1st gen Atom gets ~3300 MIPS) Also, multicore-Atom has been in the market for a while. Multicore ARM is just coming online now. It's worth noting that Intel can speed up Atom whenever they want. There are plenty of easy wins in there (eg, better execution core, faster memory controller) that they can put in if they need to keep their lead.
- ssp 16y ago
  (Lies, damn lies and benchmarks, but A8 gets ~2000 MIPS, A9 ~2500 MIPS and singlecore 1st gen Atom gets ~3300 MIPS) Measured how, and at what frequencies? Also ARMs are really starved for bandwidth. Has that improved with the Cortex A9?

pkaler 16y ago

Is ARM's power advantage really that significant for devices larger than the smart phone / tablet form factor? I'll bet $5 that the MacBook Air in the future (18-24 months) will switch to ARM once the >2GHz ARM processors start shipping en masse. The Asus Eee PCs running Android with Snapdragon processors already embed the Cortex-A9 MPCores.

jbarham 16y ago
"4GB RAM ought to be enough for anybody." ARMS's Achilles' heel is that it's only 32-bit, and I don't think anyone wants to go back to a segmented address space any time soon.
- jbrennan 16y ago
  That's a great point. Are there any 64 bit ARM chips on the horizon? I don't know much about chips, so maybe it's not even possible given the architecture.
  - 1amzave 16y ago
    I don't recall hearing any announced, though I wouldn't be surprised at all if it were currently in the works. The A15 mentioned in the article, however, I believe has something in the spirit of x86's PAE that offers an expanded (36 bits or so?) physical address space, for better or for worse (better in that you can address more memory, worse in that it's kind of an ugly hack and not a great long-term solution).
  - ryanpetrich 16y ago
    It's possible, but just like the x86-64 transition it won't be pretty.
    - protomyth 16y ago
      It might go better for ARM given that most of the more tightly controlled software that is delivered on ARMs (app store or custom embedded).