Apple’s most expensive new MacBook pro laptops are available with up to a 6-core Intel Core i9 processor and AMD Radeon Pro graphics. Unfortunately early testers have discovered that the laptop can overheat very quickly, causing the speed to drop so low that previous-gen MacBook Pro models are actually faster.

That’s kind of disappointing for a laptop with a price tag that can easily top $3,000.

But Apple says it’s aware of the problem… and the company is releasing a software update that the company says should resolve the issue.

According to Apple, there’s “a missing digital key in the firmware that impacts the thermal management system,” which could cause CPU clock speeds to take a nose dive under heavy load.

In other words, when the computer gets hot, the CPU will slow down until things cool off… which means that you could theoretically render videos or perform other CPU-intensive tasks more quickly on an older laptop with a less powerful processor.

Ars Technica notes that it was pretty easy to confirm this behavior: Cinebench, Final Cut, Adobe Premiere, Geekbench, and other programs all ran faster on a 2018 MacBook Pro with a Core i7 CPU than on a model with a Core i9 chip.

Today Apple is rolling out a software update that should correct things so that the Core i9 models do indeed run faster.

Apple says the bug fix is part of the macOS High Sierra 10.13.6 Supplemental Update that’s rolling out to users today.

It seems odd that Apple shipped a high-end computer with a bug so obvious that it was quickly discovered by some of the first people to use the laptop. But it’s good to know that Apple believes it was a software bug rather than a hardware issue… which would be a lot tougher to fix.

That said, I’d wait until we start to see post-update benchmarks before buying a 15 inch MacBook Pro with a Core i9 processor.

Update: Test results are starting to come in, and it looks like the update does help with sustained performance under heavy workloads, but some users are finding a bigger improvement than others. It will likely depend on what it is you’re doing with the laptop. 

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12 replies on “Apple acknowledges MacBook Pro CPU throttling, promises update to fix it”

  1. Ah I see Apple’s history of overheating computers continues. Steve Jobs hated CPU fans for the noise they caused. So he demanded that they be removed from the early Apple computers. To this day, Apple’s engineers try to design around using CPU fans. The G4 tower was notoriously for overheating as well.

  2. The fact that Apple is admitting this being an issue tells me that this is actually a bigger issue than they’re admitting. They would rather downplay it as a harmless firmware bug, than admit a hardware design flaw.

    I’ll bet money that the CPU is actually just going to run hotter, and Apple will insist that was they way they intended it.

    Either way, it’s a pretty big red flag that Apple doesn’t take the professional usage of their products seriously. If they did, there wouldn’t be any chance of something like this slipping past the testing phase.

    1. Agreed. I suspect that a x86 quad-core would be the sweet spot for laptops, as they will thermal throttle under load. Did they think that all six cores would be more productive at the lower clock frequency, compared to four cores at the same frequency? I suspect that the 6 cores are throttling to a lower clock than the quad-core, and the quad core is performing better on the critical single threaded task. You would have thought they saw this in prototype testing. Until Intel/AMD releases a better laptop chip, 6 cores are too much for laptop cooling.

      1. It is not that hard to drive 6 core CPU in a laptop, there are even desktop Xeon laptops.
        The issue here are ultrabooks, those thin thing just do not have a room for decent cooling.

        BTW: It’s lovely “the world” just noticed, but this is 3 years old issue as it is affecting quadcore variants as well. Not as hard, but still there was noticible throtling on Macs before, not just that pronounced as is with 6 cores.

    2. There is no issue with the CPU running hotter if it stays within operational thermal limits. If you’re going to run long CPU intensive tasks, then you should expect your system to run hot, even with a high-end CPU.

      1. …Except when it’s a laptop made of aluminum (a questionable material to use for electronics) that will burn your legs when used as… well, a laptop. I’ve used roommates Macbooks in the past that ran so hot they were impossible to keep on my lap. Some running so hot the bottoms had turned black. Always had ThinkPads and VAIOs with comparable specs to those Macbooks which never ran hot enough to do that.

    1. And for that Apple will soon be introducing the iCool Cooling Pad for MacBook Pro at $174.99 (black) There will also be an iCool Cooling Pad Pro version that comes in different colors for $199.99.
      Because there’s one born every minute, you know…

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