4 ms·

the ARM chips are, to a large extent, what enable that.

deleted 2y ago
[deleted]
School-Cotton 2y ago
Why does it matter what instruction set the chips support? The main difference between x86 and ARM is that x86 is slightly harder to decode because instructions can be variable-width. But I have never heard of instruction decoding complexity being a particularly important bottleneck.
- DonHopkins 2y ago
  You've never had to rub a bag of frozen peas all over the bottom of your x86 Macbook Pro because it was overheating and you had an imminent zoom meeting you could not miss.
  - acdha 2y ago
    AMD doesn’t have that problem, though, so is it a problem with x86 or Intel? I would bet that Apple’s CPU team could get great results with a free hand on x86, too – probably not quite as good but close.
  - jeffbee 2y ago
    The last few generations of x86 MacBooks were exceptionally bad implementations in this regard, and some of the better thermal behavior of the Apple Silicon MacBooks are things that they could just as easily done with an Intel CPU, if they had felt like it. For example, the Intel MacBooks was extremely eager to ramp its power consumption to the max, while the ARM MacBook slowly increases clock rate, one step at a time, such that it only hits max power after a long time of sustained demand.
    - hmottestad 2y ago
      I think that might have been Intels doing. They were on 14nm for 5 years or so, with each new 14nm release pushing the power budget and squeezing slightly more performance out of any corner they could find. I assume the CPU ramping was just another part of this approach. If the CPU ramps up faster it will seem fast to users and it’ll look faster in short benchmarks like Geekbench.
  - School-Cotton 2y ago
    Those chips were designed and fabbed by Intel, not by Apple/TSMC respectively. That’s the relevant difference, not the instruction set. The instruction set has only moderate impact on the chip’s frontend, and no impact on the backend. Most design decisions are unconstrained by the choice of instruction set.
- hmottestad 2y ago
  Memory ordering is also different.

deleted 2y ago

[deleted]

Why does it matter what instruction set the chips support? The main difference between x86 and ARM is that x86 is slightly harder to decode because instructions can be variable-width. But I have never heard of instruction decoding complexity being a particularly important bottleneck.

DonHopkins 2y ago
You've never had to rub a bag of frozen peas all over the bottom of your x86 Macbook Pro because it was overheating and you had an imminent zoom meeting you could not miss.
- acdha 2y ago
  AMD doesn’t have that problem, though, so is it a problem with x86 or Intel? I would bet that Apple’s CPU team could get great results with a free hand on x86, too – probably not quite as good but close.
- jeffbee 2y ago
  The last few generations of x86 MacBooks were exceptionally bad implementations in this regard, and some of the better thermal behavior of the Apple Silicon MacBooks are things that they could just as easily done with an Intel CPU, if they had felt like it. For example, the Intel MacBooks was extremely eager to ramp its power consumption to the max, while the ARM MacBook slowly increases clock rate, one step at a time, such that it only hits max power after a long time of sustained demand.
  - hmottestad 2y ago
    I think that might have been Intels doing. They were on 14nm for 5 years or so, with each new 14nm release pushing the power budget and squeezing slightly more performance out of any corner they could find. I assume the CPU ramping was just another part of this approach. If the CPU ramps up faster it will seem fast to users and it’ll look faster in short benchmarks like Geekbench.
- School-Cotton 2y ago
  Those chips were designed and fabbed by Intel, not by Apple/TSMC respectively. That’s the relevant difference, not the instruction set. The instruction set has only moderate impact on the chip’s frontend, and no impact on the backend. Most design decisions are unconstrained by the choice of instruction set.
hmottestad 2y ago
Memory ordering is also different.