Performance issues affecting Apple’s latest 2018 MacBook Pros discovered over the past week have been identified as a software flaw in the system’s thermal management software, and Apple is rolling out a macOS patch to deal with the problem.
Apple 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.
Here’s the full statement from an Apple spokesperson:
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. 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.
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.