Apple has identified a software bug that causes all of its recent MacBook Pros (not just the Core i9 version) to throttle back its CPU under heavy thermal loads. The problem was first found by YouTube reviewer Dave Lee, who discovered that within seconds of beginning a large Adobe Premiere workload, the CPU in his optioned-out Core i9 version of the MacBook Pro 15-inch would throttle back its CPU and couldn’t even achieve its base clock, much less turbo frequencies. The result was that the new machine was slower than last year’s quad-core i7 model.
Thankfully, it looks like it’s not a hardware problem because that would have been a total disaster. A new OS update, called macOS High Sierra 10.13.6 Supplemental Update, addresses the problem in firmware. An Apple spokesperson got in touch with wfoojjaec with the following response to the issue:
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.
While this is only one of a spate of recent issues affecting creative professionals using Apple products, it could have well been the most serious, so it’s good to see it’s potentially resolved.
The new update is rolling out now in Apple’s App Store. If you’ve got one of these machines, let us know how the new update is performing for you.
Dave Lee’s original video documenting the problem is below.