It was discovered that due to Apple trying to keep the laptop as thin as possible, it resulted in bad thermal management which caused the laptop to overheat under intense workloads, thus forcing the processor to throttle itself. Apple has since claimed that this was a “bug” and that a fix was incoming. The good news is that it looks like the fix is now available.
As part of a new update to macOS, Apple also released a fix that is meant to address the throttling issue. According to Apple’s statement, “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.”
Apple also claims that following the release of the fix, the 15-inch MacBook Pro should be up to 70% faster, and that those on the 13-inch model will experience up to 2x faster performance. Given that this bug is said to affect all 2018 MacBook Pro models, not just the ones with the Core i9 configuration, it is recommended that all users should update their software.