Building a macOS app to know when my Mac is thermal throttling
stanislas.blog
stanislas.blog
function isThermalThrottling() {
return true;
}
I have an M1 Max MBP now and it has been absolutely perfect.
My favorite and most painful issue was a bug in USB charging. Sometimes it would fail to charge from my monitor (USB-C) yet it would believe it’s connected. The battery would eventually run to zero and the machine would shutoff without warning. No low battery warning would be shown because it believed it was charging however it was not. Resolved with my M3.
Also fun with that generation is that you can’t plug in a dead laptop and start using it right away. Takes about ten minutes of charging before you can power it on.
Also fun, it would not establish power delivery with my monitor in this state. I’d have to plug it in with a regular charger to bootstrap it. Also resolved with my M3.
Now that it’s aged, the super capacitor for the clock no longer holds charge and the time is usually wrong on cold boot. I wish that was serviceable.
It was the third Asus computer I had owned that broke way earlier than it had any right to, and I swore a blood oath that I will not buy another Asus product.
Point is, considering how terrible that laptop was, “annoying thermal throttling” was still a considerable upgrade, so I loved it in spite of it.
A dumb thing for sure. I still like macos better than windows and I'm heavily invested in a production workflow with logic. Moving to linux would be my next move, but after making that dumb change it's quite a functional machine.
It was so much of a problem that at work we added a check that you were charging from the right ports to our internal doctor script (think like `brew doctor`).
99% of the time it works 100% of the time.
Outside of the terrible speakers, it is a nearly perfect computer. I don’t really mind a crappy speaker on a laptop since it usually lives on mute and when I need decent-enough quality audio I will plug in headphones or Bluetooth to a speaker, but YMMV.
Still, if this computer ever breaks then I will likely buy another thinkpad.
The epic takedown post of the issue on stackexchange which proved it is below, I ended up at it from somewhere on social I think.
Took awhile to diagnose that one.
Same here, but...
> I have to charge it from the right hand ports. I think that is dumb, but it did solve the issue.
I _had to_ do this for a while (around 2023, I think, not that it matters), but I no longer have to. I don't know what has changed, unfortunately; I haven't reinstalled anything, and I can't say I have uninstalled anything either. It's really weird...
It turned out a lot of the thermal throttling (kernel_task usage) on the i9 macbook pros went away if you plugged in the power on the right side, instead of the left.
Why turned out to be a chip (thunderbolt I think) that didn't have enough cooling.
https://apple.stackexchange.com/questions/363337/how-to-find...
One could also put quiet cabinet fans under the i9 Macbook Pro to make it draw air away and run markedly faster. [1]
That, combined with the keyboard failures, meant I could put a wireless keyboard on top of the laptop keyboard and use it, with fans underneath.
This is how I took it to the Apple store for warranty repair, which made a point of it having a pretty massive design flaw.
I asked them this if it was a feature of all macbooks when you buy the fastest ones to have to cool it the right way and not use the keyboard in case there might be dust in the air. The laptop was way too overspecced.
The i9 laptops were made far too thin to cool themselves appropriately in any situation, full stop.
All to say, if I could detect which USB-C port was pulling power in, on those laptops, I could guess pretty accurately what will happen on that i9.
It's sad to know the M4 Max Macbook Pro has the same issue, even though the laptop is thicker. Doesn't make me want to upgrade anymore.
[1] https://www.amazon.com/AC-Infinity-MULTIFAN-Receiver-Playsta...
I had dell and swapped it as soon as was possible to i7.
I think they just made those only because they knew there will be enough people thinking “bigger better CPU == better laptop” - and yeah seems like I am not the only one that got caught with that. But I also trusted that someone there did any testing…
When the Apple Silicon models were released, everybody attributed the lower fan noise improvements entirely to the new chip, but the newer chassis had a much better thermal solution too.
I could run my M1 MacBook Pro at similar power draws to my Intel MacBook Pro and the M1 would be very quiet while the Intel sounded like a hair dryer.
After buying it, I regularly had throttling issues. Nothing seemed to help. I tried all the recommended tricks but wasn’t getting anywhere. (I had two external monitors and using adobe creative suite back then.)
I came across some forum posts about the VRM module not being able to cool and that was making the system think it was overheating. It sounded reasonable so I decided to give it a shot. I got the thermal pads, carefully opened the laptop and applied a few layers to the various components to make sure it was touching the case (this is what makes this mod work properly, heat transfer to the aluminum case.)
It worked like magic, it felt like a brand new computer after months of bad experiences.
Only side effect was that bottom case gets really hot (that heat needs to go somewhere) so I couldn’t comfortably use it on my lap. But I never regretted doing the mod for a second!
I retired what was my then favorite computer for an M3 MacBook Air with 24gb ram and couldn’t be happier. I still have fond memories of my 16 inch 2019 MacBook Pro, if you still use that computer, please do yourself a favor and at least look into adding thermal pads to the VRM modules.
I don't remember it being super uncomfortably on my lap, though I almost exclusively wear very thick jeans so maybe I was somewhat shielded. It did get super hot.
Despite that, I did actually like the laptop a lot; it had a nice heavy weight to it, which was actually good for me since it felt very firm when I typed on it on my desk, and the keyboard was nice to type on. It benefited from low expectations because the laptop it was replacing was an Asus that was such a piece of shit that I swore a blood oath that I would never give Asus money ever again, which I have not broken.
Remember to put your coat and hat on!
On Macbooks with fans, I started tuning my fan curve with iStat Menus (https://bjango.com/help/istatmenus7/fans/#custom-fan-curve) because I noticed the default curve was lagging behind and thermal throttling kicked in before the fan even reach max speed.
For Apple Silicon specifically, I recently discovered that there is a "high power mode" (https://support.apple.com/en-us/101613) that allows the fans to run at higher speed. So I don't use the custom fan curves anymore, it helped me a lot (but it does get quite noisy on a 14" M4 Max)
For a Macbook Air, not much you can do besides closing stuff, or elevating the macbook and pointing a fan at it or things like that... but yeah it's a bit desperate!
Environment: I am currently playing with a pid control function for my gpu fan, that is instead of saying "map temp x to fanspeed y"(fan curve) say "set fan to speed needed for temp z"(pid control)
Question: is there a reason pid type control is never a thermal option? Or put another way, is there something about the desired thermal characteristics of a computer that make pid control undesirable?
As a final thought, I have halfway convinced myself that in a predictable thermal system a map would match a set of pid parameters anyway.
Why though? I generally don't care about the specific temperatures of my CPU and GPU, just that they don't get too warm, so for the CPU (AIO) I basically have "0% up until 45C, then increment up to 100% when it hits 90C" and the same for the GPU except it's always at 10%.
I guess I could figure out target temperatures, and do it the other way, but I'm not sure what the added complexity is for? The end results (I need at least) remains the same, cool down the hardware when it gets hotter, and for me, the simpler the better.
I also have two ambient temperature sensors in the chassi itself, right at the intake and the outtake. The intake one is just for monitoring if my room gets too warm so the computer won't be effective at cooling (as the summers here get really warm) and the outtake one is to check overall temperature and control the intake fans. In reality, I don't think I need to do even this, just the CPU+GPU temperature + set fan speed based on that feels simple enough to solve 99% of the things you'd like to be able to do here.
And now am about halfway through building pid fan control software and a janky gpu temp simulator so I can get some intuition on tuning the pid parameters before I set it on my actual gpu. you know, the fun part of computing. But now I am worried that perhaps there is a real reason nobody does it this way.
I think no one is doing it that way, because there is simply no need for it. Sure, when I'm 3D printing some material it sometimes need the heatbed to be exactly 45C or whatever, but why would I care about the specific temperature of my GPU? As long as it's not throttled when GPU utilization is at 100%, I'm good to go.
KISS :)
Again though I could be totally off. I just remember that being spread around as “conventional wisdom.”
Yeah, I'd understand not wanting to go between 0C and 90C over and over. But my GPU idles at around 35C, maxes out at 85C or something, and going back and fourth will surely be preferable than staying with a single temperature but voltage clock the card. Especially considering performance.
But again, I'm using my card for ML, number-crunching, simulations and VFX, you might be right that the use case of cryptocurrency mining prefers a different thermal profile.
I limit power consumption profiles and clock speeds unless higher power is required, and combine that with an oversized cooling system - keeps regular temps consistent.
For most people a fan curve is more obvious to work with and it’s largely good enough without the irritating behaviors insufficiently tuned control loops can exhibit.
I've only every seen something like this in really high reliability equipment because they're worried about repeated thermal expansion causing cracks in the boards/solder joints. There is, often, heaters available for use if the temperature gets too low. For most equipment I think that the juice just isn't worth the squeeze so it isn't done.
It's really cool that performance cores are the same between base, Pro, Max (, Ultra) chips of a generation. That really feels like Apple did it right.
I sometimes face thermal throttling because a process has gone wacko, and all I have to do is kill it. But first I have to notice it.
I rarely notice until half my battery is gone!
Quit some apps probably. I often have a bunch of stuff running in the background that I haven't bothered to close yet. It also sounds like it'd be good for detecting software that's gotten stuck in a busy loop or similar.
And/or possibly take a tea break while it chills out.
Depends on the environment, back when I had a MacBook, they still had fans, but the new ones are all passive, I think. So then the surface (or lack of it) below it would matter the most. If you keep it in your lap, on top of a hairy blanket, it'll be a lot effective at getting rid of the heat compared to if you have it sitting on a stone table, as just one example.
Edit: Seemingly the split of Air/Pro being passively/actively cooled seems to still apply today, so then checking fans, their performance and intakes/outtakes for chaff tends to be the best way, if you have a Pro.
I adjusted it to ramp the fans up at more conservative values because otherwise during intense usage periods it would hit 90C+.
https://www.reddit.com/r/MacOS/comments/1kmacsf/macbook_pro_...
Is there a similar free way for getting Windows signatures?
If your target is enterprise users convince IT users of its value and they will eventually make exceptions in their orgs for it no matter what signed or not.
So instead of the CPU or GPU going bonkers, the body gets too hot and they lose thermal dissipation capacity for the normal usage and then overheat and then throttle. They go 100% on the graphs because the throttling reduces frequencies and then load becomes too heavy.
Experiment other adapters and monitors.
aka "thermal soaking"
I also have an M2 Air and a few things seem to consistently make my machine get hot and chug and dump the battery. Idling with my machine plugged into my 4k 144hz monitor isn't an issue, but going on a Zoom call or having one too many video streams open while docked to the monitor will do it.
Is my USB controller doing more "work" when I have a video stream open? I don't think so.
My point here is that it’s not that the CPU (or the SOC to be exact) cannot handle such loads. It just that it cannot handle it when you have the device connected via USB-C and charging via USB-C too. Also, if using cheap usb-c to display port or adapters.
The corollary of this is that if that would even be possible, were your display wireless, or if you were generating frames by saving them on the disk, the CPU would not throttle.
Of-course that is of little utility here because the end result is the same: CPU gets slow, be it because of CPU, GPU or whatever.
There's another possibility. If your battery is low and you've mistakenly plugged it into a low-power USB-C source (phone charger), you will also see 100% CPU usage, low power usage, and terrible performance. Probably not the author's problem, but it's been mine more than once! It might be worth adding something to detect this case, too. You can see your charger power under "System Information"; I assume there's an API for it also.
IIRC the next generation of MacBook was the one that came with the larger power brick, which didn’t at all surprise me after that experience. Then they switched to GaN to bring the brick size back down.
When I read this I wondered "Why isn't core temperature alone not a reliable indicator of thermal throttling?". Isn't that the state variable the thermal controller is directly aiming to regulate by not letting it exceed some threshold?
I started charging it an hour or two before our session, and the issues stopped.
The amount of fur that manages to squeeze everywhere is insane.
The WORST thing, though, is that all her fur makes its way into all my musical instruments, including underneath each individual key of my upright piano (now effectively a felt piano).
On my MacBook Pro, I have come to the conclusion that Apple priorities low noise level over heat dissipation. And I have my Mac fan control to have a minimum fan speed.
If you have fans, then the heat transfer is solved, hence no vapor chamber needed, just a large copper plate to be that buffer and then wind takes heat away.
So, no magic here. Energy in must be equal to energy out.
Foolish me is considering buying a new macbook this year. I have no choice because Apple and Microsoft will do everything in their power to ship the shittiest personal computing products every year.
They produced a laptop that you can't type efficiently on?? That misses key strokes?! I had to slow my typing on those keyboards!
So, imagine the incredible contempt I have had for Apple for failing such a basic delivery. Still, their new silicon machines managed to turn my opinion around -- quite the 180. The speed improvement is genuinely remarkable, and the modern build quality otherwise seems excellent to me.
It's worth another try imo.
If you want to keep using it (maybe not as your main machine) there are some workarounds and fixes:
The simple software only way is to deactivate Turbo and/or HT. Less performance but also less power use meaning less heat. And checking gmail or browsing the web you probably wont notice much of a difference.
Or you can open it up and add thermal pads to your VRMs, finally giving them adequate cooling. Just dont touch the bottom of your macbook afterwards or rest it on your bed or couch, that thing can get hot!
you could easily put this in the App Store (maybe?) and I'd have thrown a few bucks your way.
Come along with me! We'll destroy the planet so fast that we'll all be cinders before you know it.
All we have to do is gobble the marketing speak so fast and make everything shiny and new, and we'll all be dead before you can say "Greta Thunberg."
Come die with me for thin and for stylish. Kill the animals with me for "sleek".
Die. With. Me. Now! I made an app!