3 ms·

ARM isn't doing anything magic to get hugely different performance/watt than x86, so anything passively cooled would be in the same performance ballpark as pass

ARM isn't doing anything magic to get hugely different performance/watt than x86, so anything passively cooled would be in the same performance ballpark as passively cooled x86. See, e.g., performance/watt of Altra vs Epyc: https://www.nextplatform.com/2020/03/18/stacking-up-arm-server-chips-against-x86/ https://www.nextplatform.com/2020/03/18/stacking-up-arm-serv...

lazyjones 6y ago
> ARM isn't doing anything magic to get hugely different performance/watt than x86, Apple is, though. > performance/watt of Altra vs Epyc Server CPUs are a different matter altogether, IMO.
- easygenes 6y ago
  That's yet to be seen. Though if they are, then we won't be seeing passively cooled desktop ARM PCs any time soon. Nice, quiet iMacs and Mac Minis, sure. Anyone working in production software is still going to have fans (or an expensive, enormous hunk of fins: https://www.anandtech.com/show/15261/turemetal-fanless-pc-epyc-rtx-2080 https://www.anandtech.com/show/15261/turemetal-fanless-pc-ep...) in their boxes. People running water pump loops from their PCs to underground excepted. In this era where all chips are getting power-state and speed-state shifts at millisecond speeds, eeking out even a 40% performance/watt benefit over comparable total-performance x86 SKUs in the laptop, desktop, and workstation categories would be a massive win for Apple and enough justification on top of unbridling themselves from Intel to warrant the shift. 40% benefit won't bring your average 60W desktop SKU down to a passively-coolable target. Or the 45W SKUs of a MacBook Pro class system (the passively cooled MacBooks were using 7W SKUs, and Apple axed that experiment after four years because even casual users found them too anemic to be marketable at Apple prices). Even Raspberry Pi's are getting fans these days, and that CPU never draws more than 6W: https://www.jeffgeerling.com/blog/2019/raspberry-pi-4-needs-fan-heres-why-and-how-you-can-add-one https://www.jeffgeerling.com/blog/2019/raspberry-pi-4-needs-... Lots of the ARM power wins in mobile rely on the light and infrequent use of the device. That's why Intel didn't bother with big.LITTLE style architectures until this year. This is a good jumping off point if you want to dive more into ARM perf/watt, or see how performance/core is just starting to approach that of high end desktop x86 SKUs (with the A14 likely to approach parity): https://www.anandtech.com/show/14892/the-apple-iphone-11-pro-and-max-review/4 https://www.anandtech.com/show/14892/the-apple-iphone-11-pro... That's all telling of apple likely dropping 4-16 core mobile and desktop SKUs that pull about 5W/core and are 30-40% more efficient than their x86 competition.

lazyjones 6y ago

> ARM isn't doing anything magic to get hugely different performance/watt than x86, Apple is, though. > performance/watt of Altra vs Epyc Server CPUs are a different matter altogether, IMO.

easygenes 6y ago
That's yet to be seen. Though if they are, then we won't be seeing passively cooled desktop ARM PCs any time soon. Nice, quiet iMacs and Mac Minis, sure. Anyone working in production software is still going to have fans (or an expensive, enormous hunk of fins: https://www.anandtech.com/show/15261/turemetal-fanless-pc-epyc-rtx-2080 https://www.anandtech.com/show/15261/turemetal-fanless-pc-ep...) in their boxes. People running water pump loops from their PCs to underground excepted. In this era where all chips are getting power-state and speed-state shifts at millisecond speeds, eeking out even a 40% performance/watt benefit over comparable total-performance x86 SKUs in the laptop, desktop, and workstation categories would be a massive win for Apple and enough justification on top of unbridling themselves from Intel to warrant the shift. 40% benefit won't bring your average 60W desktop SKU down to a passively-coolable target. Or the 45W SKUs of a MacBook Pro class system (the passively cooled MacBooks were using 7W SKUs, and Apple axed that experiment after four years because even casual users found them too anemic to be marketable at Apple prices). Even Raspberry Pi's are getting fans these days, and that CPU never draws more than 6W: https://www.jeffgeerling.com/blog/2019/raspberry-pi-4-needs-fan-heres-why-and-how-you-can-add-one https://www.jeffgeerling.com/blog/2019/raspberry-pi-4-needs-... Lots of the ARM power wins in mobile rely on the light and infrequent use of the device. That's why Intel didn't bother with big.LITTLE style architectures until this year. This is a good jumping off point if you want to dive more into ARM perf/watt, or see how performance/core is just starting to approach that of high end desktop x86 SKUs (with the A14 likely to approach parity): https://www.anandtech.com/show/14892/the-apple-iphone-11-pro-and-max-review/4 https://www.anandtech.com/show/14892/the-apple-iphone-11-pro... That's all telling of apple likely dropping 4-16 core mobile and desktop SKUs that pull about 5W/core and are 30-40% more efficient than their x86 competition.