Apple Says 2018 MacBook Pro Throttling is a Bug, Fix Available Now in New macOS Update

MacRumors

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Apr 12, 2001
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Apple this morning released a new supplemental update to macOS High Sierra 10.13.6, which is designed to address a bug that caused the new eighth-generation quad-core and 6-core Intel processors in the 2018 MacBook Pro models to throttle inappropriately.

The new macOS High Sierra update can be downloaded through the Software Update function in the Mac App Store on all 2018 MacBook Pro models. Today's supplemental update (build number 17G2208) is limited to those machines and is not available for other Macs. A direct link to download the update is also available.


According to Apple, the throttling seen in the higher-end 2018 MacBook Pro with Core i9 chip and other 2018 MacBook Pro models is unintentional.

The throttling issue first came to light on July 17, a few days after the first new 2018 MacBook Pros began shipping out to customers. YouTuber Dave Lee tested the top-of-the-line 2018 15-inch MacBook Pro with 2.9GHz Core i9 chip using Adobe's Premiere Pro and found that it was underperforming compared to a 2017 MacBook Pro with a Core i7 chip.


Multiple other tests followed from customers and media sites that obtained one of the Core i9 machines, and many came to the same conclusion, that there was an unusual amount of throttling that was impacting the machine's performance. It was not entirely clear if other 2018 MacBook Pro models were throttling unintentionally, but Apple's patch today suggests that was the case.

While there were many theories as to what was causing the throttling, Apple has discovered that there was a missing digital key in the firmware that impacted the thermal management system, driving down clock speeds under heavy thermal loads. This is what has been addressed in today's update.

Apple has apologized to customers who have experienced less than optimal performance on their new 2018 machines.

Following today's update, customers who own a 2018 MacBook Pro should see an appropriate level of throttling that is common to all devices under heavy load and does not impact performance to the point where the machine is underperforming compared to earlier, less powerful models.

Apple says that customers can expect the new 15-inch MacBook Pro to be up to 70 percent faster and the new 13-inch MacBook Pro to be up to 2X faster than 2017 models, as outlined in the performance results on the company's website.

Article Link: Apple Says 2018 MacBook Pro Throttling is a Bug, Fix Available Now in New macOS Update
 


aceys

macrumors member
Oct 25, 2012
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How did they not notice this in testing?
From their explanation, it sounded like the a key file was missing. Perhaps signing/including keys for their firmware is a step that's a step they bypass during internal testing, or perhaps they resign before creating the final firmware distribution and there was an issue, or something. I would bet money this firmware was working properly internally.
 

ericinboston

macrumors 68000
Jan 13, 2008
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If this is truly a bug, I applaud Apple for fixing it so fast.

I'm sure we'll see some videos of testing the new MBs at full CPU speed for several hours to see if any thermal issues arise. I run about 40 different Mac and Windows machines at 100% CPU utilization 24x7x365 and have done so for years on end...and other than the machines getting hot (of course), they do not fail at all.
 

keysofanxiety

macrumors G3
Nov 23, 2011
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I'll wait and see how benchmarks and real world tests compare before and after. People were saying temps were reaching extremely high levels when the throttling kicked in, so it didn't appear to be a "bug", rather inadequate cooling design.
Look at the temperatures of these chips in comparative Alienware or MSI gaming laptops which are 4 inches thick. These chips run hot as hell the moment you put them under load. They're going to run hot when stressed no matter what you do unless you're using your laptop in a freezer. No amount of air cooling will keep them under 80C at peak.

Plus the cooling on the tMBPs are much better than ones in those thick gaming laptops, honestly. If you take an MSI apart it's like looking into the first ever '90s laptop. They're just so lazy with space and thermal design. They throw more fans at it without any real appreciation how the heat will displace or flow.
 

geoff5093

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Sep 16, 2014
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Look at the temperatures of these chips in comparative Alienware or MSI gaming laptops which are 4 inches thick. These chips run hot as hell. They're going to run hot no matter what you do unless you're using your laptop in a freezer. No amount of air cooling will keep them under 80C at peak.

Plus the cooling on the tMBPs are much better than ones in those thick gaming laptops, honestly. If you take an MSI apart it's like looking into the first ever '90s laptop. They're just so lazy with space and thermal design. They throw more fans at it without any real appreciation how the heat will displace or flow.
This goes along with my point though, how is this a "bug" and not just a fact that the CPUs run hot and the cooling isn't adequate for 100% load without throttling? Unless the "bug" Apple fixed was making them run even hotter before throttling.
 

stevet

macrumors 6502
Apr 16, 2009
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I'll wait and see how benchmarks and real world tests compare before and after. People were saying temps were reaching extremely high levels when the throttling kicked in, so it didn't appear to be a "bug", rather inadequate cooling design.
It's possible the bug was with the temperature reporting, iow, wrong temps being reported.