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Apple Confirms MacBook Pro Thermal Throttling, Issues Software Fix (theverge.com)
An anonymous reader shares a report: For a week, we have been seeing reports that the newly released MacBook Pros run hot, which all kicked off after this video by Dave Lee. They run so hot, in fact, that the very fancy 8th Gen Intel Core processors inside them were throttled down to below their base speed. Apple has acknowledged that thermal throttling is a real issue caused by a software bug, and it's issuing a software update today that is designed to address it.
The company also apologized, writing, "We apologize to any customer who has experienced less than optimal performance on their new systems." Apple claims that it discovered the issue after further testing in the wake of Lee's video, which showed results that Apple hasn't seen in its own testing. In a call with The Verge, representatives said that the throttling was only exhibited under fairly specific, highly intense workloads, which is why the company didn't catch the bug before release. The bug affects every new generation of the MacBook Pro, including both the 13-inch and 15-inch sizes and all of the Intel processor configurations. It does not affect previous generations.
The company also apologized, writing, "We apologize to any customer who has experienced less than optimal performance on their new systems." Apple claims that it discovered the issue after further testing in the wake of Lee's video, which showed results that Apple hasn't seen in its own testing. In a call with The Verge, representatives said that the throttling was only exhibited under fairly specific, highly intense workloads, which is why the company didn't catch the bug before release. The bug affects every new generation of the MacBook Pro, including both the 13-inch and 15-inch sizes and all of the Intel processor configurations. It does not affect previous generations.
It's amazing how remorseful companies are when they get caught doing something silly :|
Here's a thought:
Fix it before you release it to the public and you won't have to apologize and tarnish your reputation.
It was actually Intel's fault. They didn't change the TDP for the 6-core CPUs. MacRumors has a more complete (and less biased) Report, encompassing three Articles:
https://www.macrumors.com/2018...
https://www.macrumors.com/2018...
https://www.macrumors.com/2018...
Fortunately, it didn't require a hardware rev. to fix...
Kudos to Apple for getting right on this issue, instead of issuing denials. No "You're holding it wrong" here!
According to the official statement from Apple (emphasis mine):
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.
So, it sounds like they forgot to digitally sign their firmware, which led to the fans or whatnot refusing to take orders, which led to the system running far too hot. That's why they're able to fix it with a software update in the first place.
Except, the CPU was not overheating. The throttling did not happen because of the CPU
The CPU is powered by a Voltage Regulator Module (power delivery module). It turns out it is this chip that is overheating - when the CPU is going full tilt, it's demanding 125W from the VRM. This causes the VRMs to heat up and when they get close to their maximum thermal limits, they send a signal to the motherboard telling it to throttle the CPUs so they draw less power so the VRMs can cool down.
Part of thermal tuning is to adjust the CPU boost speeds such that it can boost to full speed, then throttle down slightly as the VRM and CPU heat up to a new max steady-state condition where the heat generated can be dissipated.
This is in part due to a documentation error in Intel's docs regarding max thermal power dissipation values.
The good news is if you tweak the throttle settings properly, you can keep the regulators from overheating, but the CPU still performing. This is what Apple did - they optimized the settings so the VRMs will not overheat and force a sudden throttling of the system. Doing this gives you a good 20% speed boost over the old models.
The bad news is if this was caught earlier so Apple could heatsink the VRMs to the CPU like they do with the GPU, you could get up to another 10-20% in performance because you can run the boosts longer since the VRMs would heat up slower.