3 ms·
Those are all reasons why you should engineer in a thermal margin. If some proportion of machines are throttling out of the box, then most machines will start t
by jdietrich 8y ago
Those are all reasons why you should engineer in a thermal margin. If some proportion of machines are throttling out of the box, then most machines will start throttling as the thermal management system degrades. You're supposed to account for the ageing of the thermal material and clogging of the airflow path and degradation of the fan bearings. You're supposed to leave in some headroom for warm rooms, high altitude and partially blocked vents.
It's yet another symptom of Apple's preoccupation with thickness. The 2015 MacBook Pro was 18mm thick. The new MacBook Pro is 15mm thick. After all the furore over USB-C and unreliable keyboards and the loss of MagSafe, was that 3mm of z-height a worthwhile tradeoff?
- tlb 8y agoI don't think there's room for margin any more. Margin means fixing a power limit slightly lower than what the worst machine can sustain. That probably means leaving 10-20% performance on the table for average machines.
- stefan_ 8y agoNo, you don't get to blame this on the processor. Modern processors are perfectly capable of operating exactly at the limit of the cooling system they are provided. No worries there. There is no "setpoint" you need to set; the processor ramps up, then sustains. This is purely a mechanical engineering issue. They haven't designed it properly.
- tlb 8y agoChips vary considerably in the amount of power they use at a given frequency, as a result of silicon process variations. Consider table 5 in http://charm.cs.illinois.edu/newPapers/16-08/paper.pdf http://charm.cs.illinois.edu/newPapers/16-08/paper.pdf. So even with identical cooling systems, some chips will outperform others.
- EpicEng 8y agoYet that's all rather irrelevant im context considering that apple controls every aspect of their machines.