Tuesday, Nov 02, 2021, 09:23 Mac: Hardware

MacBook Pro 2021 M1 Max Under Heavy Load: Heat, Fans - And The "Throttling" Question

Since the MacBook Pro 2018, the question for new Apple notebooks has been how the devices react to sustained load and how hot they run. Remember: The performance of the 2018 model dropped extremely as soon as the temperature increased. The processors were quickly throttled so much that the actual performance was even lower than the predecessor models. Apple corrected the behavior, but the issue drew attention to a general problem. Previous generations of the MacBook Pro also had to resort to "throttling" and throttle the clock rate, although not as much as it was initially the case with the MacBook Pro 2018.



M1, M1 Max and Intel chips under continuous load.
When we pitted the fanless MacBook Air M1 against the Mac mini M1 a year ago, we could also see the importance of cooling. After half an hour under maximum load, the MacBook Air M1 came to about 25 percent less performance than the actively air-supplied Mac mini. However, Apple apparently made further adjustments over the course of last year, because our recent throttling test revealed different values. Here's how it looks in our current test:

The diagram shows how long the different devices need to execute their test tasks under full load of CPU and GPU. What is striking about the MacBook Air M1 (yellow bar) is that it keeps the performance relatively constant, but goes into a kind of emergency mode after 30 minutes and therefore massively slashes the performance. The Mac mini M1 does not have to resort to such measures, nor does the MacBook Pro 2021 with M1 Max.

The MacBook Pro with Intel processor (red line) shows a different behavior. The performance drops significantly very quickly and then remains on a constant level for 20 minutes. After that, however, there is a further drop in performance as the chip is clocked down.

Heat development of the MacBook Pro M1 Max.
Apple mentioned that the cooling system of the new MacBook Pro is 50 percent more powerful. However, this did not say anything about how much the fans have to be used. You can find our observations of the heat and fan behavior below:

  • After 20 minutes of full throttle, the MacBook Pro continues to operate almost completely silently - only with the ear on the case can a quiet whisper be heard. The case temperature on the upper side is around 110° degrees at this point. The Intel-based device (MacBook Pro 2017) is quite different, as it already made noise at full volume after three minutes. At the same time, it got so hot on the bottom that you can hardly put it down on your thighs.
  • After 30 minutes, the temperature of the aluminum part above the keyboard increased to 125° degrees, and the underside is at 97° degrees. It can still be used as a "lap"top, though.
  • After 40 minutes, the situation was exactly the same as before: no fans, no unpleasant waste heat and certainly no throttling due to excessive heat development. At this point we ended the test, because there were no more changes.

Conclusion of the test
If the pure benchmark results were already astonishing, the load test provides even more excitement. Since the beginning of the M1 era, we already knew that scrolling in the browser window doesn't have to trigger a fan emergency anymore. What the M1 Max achieves in performance, while still remaining comparatively cool, is fabulous. It should never be possible to wrestle activity from the fans in everyday use. Louder work can only be assumed during hours of high load in warm rooms. In any case, the cooling system seems to be more than sufficient to prevent throttling - one can therefore ask why the "High Power Mode" is offered.

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