3 ms·

>> Except this completely defies the logic in the first part of the paragraph that the power and cooling do not affect the performance in the short burst tests.

>> Except this completely defies the logic in the first part of the paragraph that the power and cooling do not affect the performance in the short burst tests. Those ARM chips won't get faster, they will just have the same speed as they have today. I think the logic is that with better cooling, you could have the same ARM chip running at higher voltage and clock speeds, under sustained load, and the result would compare favorably for the ARM chip both on 'burst performance' and 'sustained performance' metrics. What makes you think this is not true? Is there anything in fast ARM chip designs that makes them only optimized for burst loads and hence inherently unusable for sustained loads? In a sense, you could make the same argument for x86 desktop CPU's, seeing they are also not able to maintain boost clocks very long for sustained loads either. The article specifically addresses this point: current ARM chips are mostly held back by the passive cooling of phones and tablets, which is a property of the device itself and not of the possible performance you could theoretically get from the CPU.

LoSboccacc 8y ago
> the logic is that with better cooling, you could have the same ARM chip running at higher voltage and clock speeds so it's netburst all over again, see how that turned out.
- detaro 8y ago
  No, the fact that small, passive-cooled devices have to be thermally limited, and the same chips with better cooling can run at high speeds longer is not "Netburst all over again".
  - LoSboccacc 8y ago
    but that's the whole point ain't it? there's zero indication that making cooling better would make the chip faster. higher voltage could, cooling being a consequence. at best cooling could stave off throttling. but increasing voltage at 7nm gets you massive leakage currents real fast so you hit a wall in scaling that's not just about cooling it better. so yes, basically all the misconception that netburst had about power, density and scaling, reproposing themselves as "but no! it's about the cooling" basically everyone defending this is assuming power, cooling, clock speed and transistor density are independent variables, which aren't. > "the fact" yeah.
    - w0utert 8y ago
      That's all true in the context of trying to boost voltage/clock speed on a chip that is already running close to thermal limits when using a stock active heatsink (which are already huge). And yet, even in that context people are able to overclock parts rated for 3Ghz to over 5Ghz using extreme cooling solutions. In the context of building desktop-grade ARM CPU's we're not talking about 5Ghz overclocks, but about going from passive cooling in cramped space without any airflow, to something more like a laptop or workstation with active cooling. You also don't need to go all the way up to 5 Ghz, the A12X for example runs at a maximum clock speed that is 40% lower than the base clock of the i7 the benchmarks the article is referring to, yet it manages to be already quite close in terms of performance.
    - detaro 8y ago
      Look at modern laptops/tablets/mini-PCs using Intel CPUs. The exact same part, with different cooling systems and accordingly set power profiles, is used in different devices, with performance differing accordingly. Variants of throttling (or temporary boost, but that's the same with different names) based on cooling performance happen in lots of compact devices (x86 or ARM), which better cooling can delay or completely remove. Of course there's limits to that, and a 5W part won't just scale up to a good 50W part, but there is room there. These approaches weren't really a thing for Netburst, which was firmly a desktop architecture from the start and got pushed higher and higher.
      - LoSboccacc 8y ago
        > The exact same part they have less cache on board, less cores, different integrated gpu; they don't support higher frequency ddr and they have limits on the memory bandwidth. are you sure you don't want to check in with any of those facts of yours before pursuing further conversation? modern cpu architecture are built to fit their own constraints maximally. once you start changing voltage and make some part of the cpu hotter than the original spec you'll might very well find out whole part of the chip need to be shifted around or redesigned to spread the load differently. of course a slower chip is better performing watt for watt, the whole point is that the relationship is not linear! that doesn't mean you can just upclock the chip adding cooling, neither that a upclocking a chip won't require a significant redesign. those parts are already pushing their envelope, or are you implying Apple is specifically wasting money on their chips? this seems a good time to remind how clock speed and chip features are intertwined with yeld and impurities https://en.wikipedia.org/wiki/Overclocking#Factors_allowing_overclocking https://en.wikipedia.org/wiki/Overclocking#Factors_allowing_... it's not like "just add cooling to the cpu and it'll tolerate a higher voltage" - not at all.

LoSboccacc 8y ago

> the logic is that with better cooling, you could have the same ARM chip running at higher voltage and clock speeds so it's netburst all over again, see how that turned out.

detaro 8y ago
No, the fact that small, passive-cooled devices have to be thermally limited, and the same chips with better cooling can run at high speeds longer is not "Netburst all over again".
- LoSboccacc 8y ago
  but that's the whole point ain't it? there's zero indication that making cooling better would make the chip faster. higher voltage could, cooling being a consequence. at best cooling could stave off throttling. but increasing voltage at 7nm gets you massive leakage currents real fast so you hit a wall in scaling that's not just about cooling it better. so yes, basically all the misconception that netburst had about power, density and scaling, reproposing themselves as "but no! it's about the cooling" basically everyone defending this is assuming power, cooling, clock speed and transistor density are independent variables, which aren't. > "the fact" yeah.
  - w0utert 8y ago
    That's all true in the context of trying to boost voltage/clock speed on a chip that is already running close to thermal limits when using a stock active heatsink (which are already huge). And yet, even in that context people are able to overclock parts rated for 3Ghz to over 5Ghz using extreme cooling solutions. In the context of building desktop-grade ARM CPU's we're not talking about 5Ghz overclocks, but about going from passive cooling in cramped space without any airflow, to something more like a laptop or workstation with active cooling. You also don't need to go all the way up to 5 Ghz, the A12X for example runs at a maximum clock speed that is 40% lower than the base clock of the i7 the benchmarks the article is referring to, yet it manages to be already quite close in terms of performance.
  - detaro 8y ago
    Look at modern laptops/tablets/mini-PCs using Intel CPUs. The exact same part, with different cooling systems and accordingly set power profiles, is used in different devices, with performance differing accordingly. Variants of throttling (or temporary boost, but that's the same with different names) based on cooling performance happen in lots of compact devices (x86 or ARM), which better cooling can delay or completely remove. Of course there's limits to that, and a 5W part won't just scale up to a good 50W part, but there is room there. These approaches weren't really a thing for Netburst, which was firmly a desktop architecture from the start and got pushed higher and higher.
    - LoSboccacc 8y ago
      > The exact same part they have less cache on board, less cores, different integrated gpu; they don't support higher frequency ddr and they have limits on the memory bandwidth. are you sure you don't want to check in with any of those facts of yours before pursuing further conversation? modern cpu architecture are built to fit their own constraints maximally. once you start changing voltage and make some part of the cpu hotter than the original spec you'll might very well find out whole part of the chip need to be shifted around or redesigned to spread the load differently. of course a slower chip is better performing watt for watt, the whole point is that the relationship is not linear! that doesn't mean you can just upclock the chip adding cooling, neither that a upclocking a chip won't require a significant redesign. those parts are already pushing their envelope, or are you implying Apple is specifically wasting money on their chips? this seems a good time to remind how clock speed and chip features are intertwined with yeld and impurities https://en.wikipedia.org/wiki/Overclocking#Factors_allowing_overclocking https://en.wikipedia.org/wiki/Overclocking#Factors_allowing_... it's not like "just add cooling to the cpu and it'll tolerate a higher voltage" - not at all.