4 ms·

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 conse

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.
  - w0utert 8y ago
    >> those parts are already pushing their envelope, or are you implying Apple is specifically wasting money on their chips? I would say the envelope Apple is pushing with their designs is currently almost exclusively bound by the working environment their SoC's run in: limited cooling and limited battery. They probably spend more time optimizing their software to make more efficient use of their chips than optimizing their cooling solution, because there simply is no room for fans and airflow. That does not say anything about how suitable these chips could be with better cooling though. The fact that they are optimized for low power does not mean they cannot, or be redesigned minimally, to run at higher clock speeds. In fact, that's exactly what Apple is already doing, by using virtually identical variations of their SoC's across iPhone, iPad and AppleTV, running at different clock speeds. >> are you sure you don't want to check in with any of those facts of yours before pursuing further conversation? >> this seems a good time to remind how clock speed and chip features are intertwined with yeld and impurities I don't know why you need to be so dismissive and agressive in your comments, especially since so far you have not brought up anything countering any of the arguments made by anyone else in this thread. Maybe you can address the observation already made by dotaro about Intel making literally 20 different variations of the same CPU's, scaling from the ULV end with low clock speeds and limited cooling options, all the way up to the HPC end where clock speeds, TDP, etc. are large multiples of what goes into the ULV parts? What makes you think this is only possible with x86 chips and not with the ARM-based designs Apple uses? Do you think each variation of an Intel x86 chip from the same generation is a completely different design that was built from the ground up to fit that particular use case? You seem to be stuck on equating having the option of a better cooling solution so you can push the design of e.g. an A12 chip to higher clock speeds and close the already small gap with x86 chips, with going full-scale Netburst architecture with low IPC compensated by crazy clock speeds and ultra-deep pipelines, by means of nothing more than pushing an imaginary turbo button and call it a day. Nobody suggested that but yourself.

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.
- w0utert 8y ago
  >> those parts are already pushing their envelope, or are you implying Apple is specifically wasting money on their chips? I would say the envelope Apple is pushing with their designs is currently almost exclusively bound by the working environment their SoC's run in: limited cooling and limited battery. They probably spend more time optimizing their software to make more efficient use of their chips than optimizing their cooling solution, because there simply is no room for fans and airflow. That does not say anything about how suitable these chips could be with better cooling though. The fact that they are optimized for low power does not mean they cannot, or be redesigned minimally, to run at higher clock speeds. In fact, that's exactly what Apple is already doing, by using virtually identical variations of their SoC's across iPhone, iPad and AppleTV, running at different clock speeds. >> are you sure you don't want to check in with any of those facts of yours before pursuing further conversation? >> this seems a good time to remind how clock speed and chip features are intertwined with yeld and impurities I don't know why you need to be so dismissive and agressive in your comments, especially since so far you have not brought up anything countering any of the arguments made by anyone else in this thread. Maybe you can address the observation already made by dotaro about Intel making literally 20 different variations of the same CPU's, scaling from the ULV end with low clock speeds and limited cooling options, all the way up to the HPC end where clock speeds, TDP, etc. are large multiples of what goes into the ULV parts? What makes you think this is only possible with x86 chips and not with the ARM-based designs Apple uses? Do you think each variation of an Intel x86 chip from the same generation is a completely different design that was built from the ground up to fit that particular use case? You seem to be stuck on equating having the option of a better cooling solution so you can push the design of e.g. an A12 chip to higher clock speeds and close the already small gap with x86 chips, with going full-scale Netburst architecture with low IPC compensated by crazy clock speeds and ultra-deep pipelines, by means of nothing more than pushing an imaginary turbo button and call it a day. Nobody suggested that but yourself.