The bugfix came in the form of an additional update for macOS High Sierra 10.13.6, which many new owners of MacBook Pro have now installed on their machines. Several MacBook Pro owners and media sites have tested the new patch, and the results appear to be largely positive – most of the throttle problem has been resolved and the machines are working better.
For example, CNET did something before and after testing with a video encoding test. Before the patch, the tested Core i9 machine saw frequent fluctuations in internal temperature and CPU clock speed, while after the upgrade, CPU throttling in the Core i9 MacBook Pro stopped, with the CPU clock speed and internal system temperature remaining stable.
Macworld shared some tentative test results from its 4K Adobe Premiere test and obtained similar results with the clock frequency at or above the baseline rather than spiky throttling. Macworld estimates that before the patch, the Core i9 15-inch MacBook Pro 2018 was 11 percent faster than the comparable 2.9GHz Core i7 MacBook Pro last year. After the patch "it's more like 20 percent faster."
Preliminary Results from our 4K Premiere Test:
2017 2.9GHz Core i7: 90 min
2018 Core i9 Patch Before: 80 min
2018 Core i9 after Patch: 72 min
Also, very even watches at or above the base instead of spiky throttling. pic.twitter.com/4CtgJ72pRt
– Macworld (@macworld) July 24, 2018
Dave Lee, who highlighted the throttling issue in the first place, tweeted some post-patch test results and said the performance was much better.
sooo much better pic.twitter.com/AKIeXYpKAH
– Dave Lee (@ Dave2Dtv) July 24, 2018
Geekbench Labs founder John Poole tested the Core i9 MacBook Pro 2018 after the Patch and found that it was faster with a more stable processor frequency. It was slightly slower than the Core i7 MacBook Pro 2018. Poole says that while long-running multithreading tasks perform similarly on the Core i9 and Core i7 machines, single tasks and low threading tasks on the i9 should be faster.
After I installed the latest update from Apple, I re-run the geekbench build test on the i9. It's a bit faster, but the processor's frequency remains stable during setup (which is reassuring).
Still technically slower than the i7, but close enough that it does not really matter. pic.twitter.com/hOogCt6ZB0
– John Poole (@jfpoole) July 24, 2018
MacRumor's Reader Aea has pre-patch and post-patch cinebench Benchmarks shared with the 15-inch MacBook Pro with Core i9 chip shows the jump in the score after the update.
Several Reddit users with 2018 MacBook Pro models have shared their benchmark and test results and seen significant improvements after installing the supplemental update. For example, this image from Reddit user XNY shows a before-and-after image of a 13-inch MacBook Pro 2018 with a Core i5 chip.
Another reddit user (apple_) has confirmed that his Core i9 is getting better and better after the update.
I have done all the tests and can confirm for myself that I constantly reach the basic clock frequency or higher in the Tortest with Prime 95. Even if I pass between 4 and 3 tests with 2.9 – 3.9. I also ran Cinebench and OpenGL got 106 fps and the CPU test gave me over 1000 for each test. Thanks Apple for this quick fix and thank you for bringing all these issues to light.
The throttling issue was discovered just days after the release of the MacBook Pro models when creator Dave Lee tested the top-of-the-line 2018 15-inch MacBook Pro with 2.9GHz Core i9 Chip with Adobe Premiere Pro and found that it was under performance compared to a 2017 MacBook Pro, due to what Lee said was an "unacceptable" level of throttling.
Apple attacked Lee and worked with him to replicate his workflow to find the cause of the error. Apple found that the MacBook Pro firmware lacked a digital key that compromised the thermal management system and drove down clock speeds at high thermal loads. This problem seemed to have affected all of the 2018 MacBook Pro models.
The problem appears to have been successfully addressed in today's macOS High Sierra supplement update, and Apple has apologized to customers who did not perform well on their new 2018 machines.
Customers who own a 2018 MacBook Pro and have not installed the update should do so immediately to see the performance improvements for themselves.