Apple Issuing Fix for 2018 MacBook Pro Throttling

(Image credit: Apple)

After complaints from YouTubers and customers online, Apple today announced that it has a discovered a bug in its 2018 MacBook Pros with 8th Gen Core i7 and Core i9 processors that affects performance. The company is issuing a software update today that it claims will fix the issue. The bug affects thermal management, which could affect clock speeds.

"Following extensive performance testing under numerous workloads, we've identified that there is a missing digital key in the firmware that impacts the thermal management system and could drive clock speeds down under heavy thermal loads on the new MacBook Pro," an Apple spokesperson told the press in a statement. "A bug fix is included in today's macOS High Sierra 10.13.6 Supplemental Update and is recommended."

"We apologize to any customer who has experienced less than optimal performance on their new systems. Customers can expect the new 15-inch MacBook Pro to be up to 70% faster, and the 13-inch MacBook Pro with Touch Bar to be up to 2X faster, as shown in the performance results on our website."

It's not quite clear what a "digital key" means here, but if the thermals improve, it could restore promised clock speeds.

Much of the current uproar came after YouTuber David Lee demonstrated throttling in a video called "Beware the Core i9," in which he demonstrated that the Core i9 throttled hard and sometimes ran below base clock speed. It's not a good look for Apple, which just updated its hardware to better accommodate professional users.

The laptop also features a membrane that Apple says is meant to keep the keyboard more quiet, but some patents suggest that it also fixes issues with dust.

We're expecting a MacBook in soon for review, so we'll see if the update makes the 2018 MacBook Pros ready for prime time.

Andrew E. Freedman

Andrew E. Freedman is a senior editor at Tom's Hardware focusing on laptops, desktops and gaming. He also keeps up with the latest news. A lover of all things gaming and tech, his previous work has shown up in Tom's Guide, Laptop Mag, Kotaku, PCMag and Complex, among others. Follow him on Threads @FreedmanAE and Mastodon

  • TJ Hooker
    A few comments I've seen indicate the the Macbook fan profile is very conservative, such that fans are only spinning at moderate speeds even as the CPU is overheating and aggressively downclocking. If they're claiming to fix this using software, it seems that adjusting the default fan profile is one of the only things they can do. No idea how this relates to the mentioned "digital key" though.
  • oneblackened
    It's probably a new fan curve. Might be different power draw algorithms as well.
  • Gillerer
    My take on the "digital key" part is that OSX probably requires each system component (software/driver) to be digitally signed. If a component's validity and authenticity can't be verified, the OS will just refuse to use it.

    Having a component of thermal management disabled could make the software side inoperational, leading to hardware-imposed throttling once the temperatures climb too high. This hypothesis is also compatible with the fact that the fans don't ramp up even when throttling: the software that should instruct them to do so isn't working.
  • closs.sebastien
    I'm not sure of how a software update can make the cooling more efficient... The heatspreader/heatpipes are undersized, that's it. it is a conceptual issue, hardware issue.
    Even if they make the fan much faster, I doubt that it's enough to cool a 3.8 ghz turbo mode without make it throttling.
  • John Nemesh
    Can't wait to see how a software patch fixes a hardware problem! Good luck, those of you who worship at the grave of Jobs!
  • Giroro
    What does "digitial key" mean in this context.

    If Apple wants people to believe that they can fix something like thermal (or vrm?) throttling in software, then they better be prepared to offer a real explanation instead of trying to breeze past it with Star Trek technobabble.
  • stdragon
    Reducing voltage a little while ramping up the fan speed would be my guess.
  • pjmelect
    I have read that it is not the CPU that is throttling but is the VRM that are overheating and limiting current.
  • jn77
    There is an easy fix. Make them as thick as a ThinkPad and add 5 pounds to the weight. It will get rid of heat like a mother *
  • TJ Hooker
    Looks like the update did bring some improvement. It looks like previously the CPU would aggressively try to hit max turbo clocks (4.3 GHz for all core), overheat, throttle back (sometimes well below even base clock), cool down a bit, and then repeat. So the frequency was bouncing all over the place. With the update it seems to more intelligently target a boost clock that's more or less sustainable (~4.0 GHz). It seems like this improved overall performance, in addition to making it more consistent.

    Hopefully there will be some more comprehensive investigation (I'm still curious to see if fan speed/noise changed).