alt.hn

12/28/2025 at 11:51:42 AM

Building a macOS app to know when my Mac is thermal throttling

 https://stanislas.blog/2025/12/macos-thermal-throttling-app/

by angristan

12/28/2025 at 7:00:27 PM

I had the 2019 Macbook Pro i9, so I think a function to determine thermal throttling could be written very simply:

    function isThermalThrottling() {
        return true; 
    }
Seriously, I loved that computer for the most part but I was a little annoyed that I paid a lot of money for the i9 CPU just to get worse performance than the i7.

by tombert

12/28/2025 at 9:37:15 PM

I am writing this comment from a 2019 i9. I have to charge it from the right hand ports. I think that is dumb, but it did solve the issue. I have no idea how I came to that conclusion (i almost certainly read about it somewhere), but there were certainly a couple of weeks where it was driving me crazy.

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.

by scarecrowbob

12/28/2025 at 10:03:01 PM

It was definitely a relatively well known problem with the 2019 MBP on the internet at some point. I found a Reddit thread linking to a news article about this. https://www.reddit.com/r/mac/comments/vi3grj/you_should_char...

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`).

by auscompgeek

12/29/2025 at 12:47:33 AM

I help out with an emulation community. Any time anyone with a 2019 MBP comes in with issues, I stop them from giving any more details and just have them check this first.

99% of the time it works 100% of the time.

by Klonoar

12/28/2025 at 10:04:14 PM

FWIW, I replaced that MacBook with a Thinkpad (AMD Edition) about a year, and i have been extremely with it. Not only was it one of the easiest Linux installs I have ever had, but the hardware feels solid, the keyboard (while not one of the legendary classic Thinkpad keyboards) is nice to type on, the 4K screen looks nice, and everything just feels well built and snappy.

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.

by tombert

12/29/2025 at 3:17:14 AM

> I am writing this comment from a 2019 i9.

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...

by thatwasunusual

12/28/2025 at 10:08:08 PM

You were not alone.

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.

by j45

12/29/2025 at 3:05:43 AM

My old 2015 MBP would lose internet if I had a display and charger plugged in at the same time.

Took awhile to diagnose that one.

by tmpz22

12/29/2025 at 3:15:19 AM

I had the 2019 MacBook Pro i9 too. Applying thermal pads to the VRM module fixed the throttling problem. It was like a brand new computer, the one I thought I was purchasing.

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.

by shalomv

12/29/2025 at 5:06:01 AM

I did the same mod on my 2019 MBP 16, and I got two more years of useful life out of it in exchange for nearly burning myself a few times when watching a movie or running some kind of CPU-intensive task with the laptop touching my body (even through a t-shirt or jeans!). Eventually, the airflow from the cooling fans started to weaken and the display flex cable started to get a bit squirrely on me. I'm on a 14" M-series MBP now, and it's freakishly quiet and efficient.

by Centigonal

12/28/2025 at 11:10:37 PM

I think it was just any laptop with i9 just bad CPU for a laptop.

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…

by ozim

12/29/2025 at 1:53:48 AM

On these MacBooks the VRR modules were particularly prone to overheating and throttling because of the GPU regardless of the CPU model.

by achandlerwhite

12/28/2025 at 10:00:52 PM

There is one pretty epic stackoverflow post that AI searches probably won't find.

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...

by j45

12/28/2025 at 7:07:56 PM

I had that problem as well. Especially when connected to two external monitors. I did not love the machine and the M1 Max was such a big upgrade because of that and I could upgrade to the m3 max later and give my m1 to somebody else. Both apple silicon machines are going strong for a long time I guess.

by merb

12/28/2025 at 8:35:16 PM

I had that laptop and it is the worst computer I have ever owned. As soon as you booted the fans would start spinning. There were sometimes kernel panics when plugging or unplugging Thunderbolt devices.

I have an M1 Max MBP now and it has been absolutely perfect.

by lbourdages

12/28/2025 at 10:18:22 PM

Same! Still have it as a side machine.

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.

by thedougd

12/28/2025 at 10:26:53 PM

I had heard of the super capacity issue, and while mine had not shown any symptoms of that I decided to sell it before it did.

by tombert

12/28/2025 at 10:21:34 PM

The laptop it was replacing was a terrible Asus computer that literally started falling apart and delaminating after about six months. It felt like it would break a bit more every time I touched it. Asus themselves was wholly unwilling to do anything about it, and they acted like I had been juggling with the damn thing when all it ever did was live on my desk or next to my bed.

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.

by tombert

12/28/2025 at 11:40:12 PM

The thermal solution for the last generation of Intel MacBook Pros was very bad.

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.

by Aurornis

12/28/2025 at 8:16:02 PM

I had a Mid-2015 MacBook Pro with an i7 and I still ran the fans at full speed at all times (actually above full speed). I had a couple fan failures due to that, but otherwise I think it was worth it.

by LoganDark

12/28/2025 at 10:09:02 PM

2014-15 were among the best macbooks ever made. All laptops fail eventually from pushing them extremely hard.

by j45

12/29/2025 at 3:56:19 AM

I had that one with 64gb: got a new one twice but could not get it to act normal. It just got so incredibly hot, it was uncomfortable. It was one of my worst hardware purchases.

by anonzzzies

12/29/2025 at 5:27:35 AM

Mine was also 64GB. I was working at Apple at the time and I had a discount that I wanted to maximize, so I went onto the shop website and maxed out literally every option available to me. Total damage ended up being like 4 grand.

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.

by tombert

12/28/2025 at 3:14:23 PM

Seems like good work. From what I've heard developing on MacOS has not gotten easier over the years. I do question the point, though. I suppose there's merit in knowing if your configuration causes thermal throttling, but what are you able to do about it? There's no fan profile to tweak or anything. Can you undervolt them?

by Neywiny

12/28/2025 at 3:23:12 PM

> but what are you able to do about it?

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!

by angristan

12/28/2025 at 4:20:47 PM

An open question on fan curves

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.

by somat

12/28/2025 at 4:35:27 PM

> "set fan to speed needed for temp z"(pid control)

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.

by embedding-shape

12/28/2025 at 5:27:48 PM

In my case the gpu fan was not changing speed automatically, (something, something, linux) which I discovered after an embarrassingly long time of poking at other things trying to figure out why my system was crashing so much. And now instead of doing the sane thing and figuring out how to get the fan speed map to work, I thought about it and came to this conclusion "I want my temps to be set value, say 45C, why not use a closed loop controller to find the fan speed necessary for that temp at any load?"

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.

by somat

12/28/2025 at 5:45:02 PM

Aren't you ultimately gonna have to figure out why you cannot change the speed on the GPU, regardless of the approach? And then you're just back at square one?

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 :)

by embedding-shape

12/28/2025 at 5:28:10 PM

This could be total nonsense and I am definitely out on a limb here, but I remember from my amateur crypto mining days (almost 15 years ago wow) that keeping everything relatively consistent is better for the longevity of your hardware (GPU/CPU mainly). Some people obsessed over getting temps as low as possible but that’s not very productive, diminishing returns and all of that. There is just generally a healthy temperature to keep things operating at most of the time, coupled with how hard you push the component in question (while not putting too much strain on your fans either). Basically: swinging/fluctuating is not good, consistency is good.

Again though I could be totally off. I just remember that being spread around as “conventional wisdom.”

by Forgeties79

12/28/2025 at 5:46:55 PM

> Basically: swinging/fluctuating is not good, consistency is good.

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.

by embedding-shape

12/29/2025 at 11:59:10 PM

My CPU/GPU basically lives between 35-60C, I don’t mess with voltage. Just a huge case with lots of air flow/fans.

by Forgeties79

12/28/2025 at 5:50:04 PM

You're speaking the truth, as this is not nonsense - it is correct. At the micro level, thermal expansion/contracting is occurring across the variety of the circuit board materials and components. Hot is fine (not too hot), but it is the consistency that makes for longetivity.

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.

by The_President

12/28/2025 at 6:40:22 PM

Yeah that was my understanding as well. Basically it comes down to how much you are warping/straining the materials. It all seems rather intuitive to me but this is not my area of expertise and just because something makes sense doesn’t mean it’s correct lol

by Forgeties79

12/28/2025 at 8:32:20 PM

> 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?

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.

by mveety

12/28/2025 at 5:42:40 PM

PID loops work best when you have active control for both heating and cooling. PIDs are also best when you have a single optimal point you’re aiming at, there’s a kind of fundamental mismatch here in that there isn’t really a “too cold” for your system, you’re just aiming to keep the system below an upper limit while hopefully keeping fan noise to a minimum (otherwise you’d just send it and run at max 24/7).

by kec

12/28/2025 at 5:54:29 PM

A simple PID wants to keep it at a setpoint, but it’s easy enough to layer a target change on top of it, some hysteresis so it’s not pulsing on and off, perhaps with control authority depending on the the target, etc. but then that gets complicated and usually manufacturers aren’t going to expose those sorts of tunings to the user.

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.

by Espressosaurus

12/28/2025 at 7:19:14 PM

It would be cool if the bottoms of MacBooks weren’t flat and instead wavy or rippling to increase surface area. There are probably a lot of cool designs (ayyyyy) you could machine in.

by tyre

12/28/2025 at 7:36:47 PM

There are laptops like that (e.g. the fanless Lenovo Chromebook Plus 14). No idea if it was actually engineered like that for thermal reasons.

by Marsymars

12/28/2025 at 8:19:16 PM

Is there a value to increasing surface area on the top or bottom case of a MacBook? I'd imagine most of the thermal management is achieved by fan-directed airflow through the internal heatsinks and convection through the keyboard.

by LoganDark

12/29/2025 at 4:02:06 AM

Well the MacBook Air has no fans so it’s a different beast from a design perspective. If I recall, at least with an earlier m series MacBook, notably improved performance could be gained by inserting a thermal pad between the chassis’ bottom panel and the compute module. Apple probably didn’t do this in an effort to avoid uncomfortably hot temperatures contacting people’s thighs.

by Lord-Jobo

12/29/2025 at 10:12:28 AM

Oh, I saw that video too!: https://www.youtube.com/watch?v=NnllZYEhvDQ

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.

by LoganDark

12/28/2025 at 4:33:34 PM

I've been using Macs-Fan-Control since I picked up a Mac M1 a few years back and it works great. It lets you control the fan RPM based on CPU Core values.

I adjusted it to ramp the fans up at more conservative values because otherwise during intense usage periods it would hit 90C+.

https://github.com/crystalidea/macs-fan-control

by vunderba

12/28/2025 at 3:25:41 PM

I wanted this app to exist. Now it does!

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!

by jtbayly

12/28/2025 at 3:27:10 PM

You know what, fair point. I know because my fans go haywire (except that one time my fans decided to just not work until I ran some incantations. The joys of Linux). If you're passively cooled, you get no feedback on CPU load. Makes sense.

by Neywiny

12/28/2025 at 4:40:39 PM

Indeed, that's why apps like iStat Menus, Stats, Sensei etc (for macOS at least) are very useful, I keep the CPU usage and power usage in my menu bar at all times, this is very useful on battery. For example I know that my Macbook Air idles at ~2W-5W, so if I'm doing nothing special and it's using 15W, a process is doing some funny stuff

by angristan

12/28/2025 at 3:32:59 PM

Yeah I’m on a MacBook Air, so no fans.

by jtbayly

12/28/2025 at 4:31:58 PM

> but what are you able to do about it

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.

by nicoburns

12/28/2025 at 5:01:45 PM

I use TG Pro on my Macbook Pro to auto-cool my Mac. It drives me crazy that Apple lets your Mac burn to a crisp before kicking on the fans.

by giancarlostoro

12/28/2025 at 6:43:21 PM

Is Apple actually letting the Mac burn to the point at which it has damage or other negative consequences? I've definitely observed they delay the fans until they're absolutely needed, but I trust their thermal management to not actually cause harm. (besides a warm lap)

by varenc

12/28/2025 at 4:33:23 PM

> but what are you able to do about it?

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.

by embedding-shape

12/28/2025 at 4:57:30 PM

New macbooks still have fans. Depending on the model.

by hu3

12/28/2025 at 4:47:49 PM

MacBook Air is passive, MacBook Pro is not

by saagarjha

12/28/2025 at 3:22:39 PM

You can move to a colder place or turn the room temperature down.

by amelius

12/28/2025 at 3:25:25 PM

In the northern hemisphere you can just open a window at this time of the year.

Remember to put your coat and hat on!

by nottorp

12/29/2025 at 3:03:16 PM

They didn't say anything about that in the adverts.

by amelius

12/28/2025 at 5:50:49 PM

He could get notarization and code signing for free if he puts it into Homebrew. I would love to get it via that distribution mechanism.

by e40

12/28/2025 at 6:13:51 PM

This is great to hear.

Is there a similar free way for getting Windows signatures?

by xenonite

12/29/2025 at 3:42:43 AM

I have not found one since the CA/BF voted to require hardware security modules for signing certificates. The cheapest option for an individual is via Microsoft, $10/month and a relatively painless identify verification lets you do cloud signing. They have enabled and disabled signups for the individual option, though, and it's unclear if it will be there permanently. Other options are ~$300/year and up. Also annoying is that Azure cloud signing works on GitHub Windows runners but not GitLab ones.

by beaugunderson

12/29/2025 at 2:25:28 PM

I’m not super familiar with windows code signing anymore but fewer people care about it on windows (because it isn’t required). It’s definitely a small hurdle to be sure but I think you’d really only lose out on enterprise users at that point. I think code signing might only matter if the installer is built in certain ways (i.e. it’s an exe instead of using an msi to install, if someone knows better please correct this).

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.

by c0wb0yc0d3r

12/28/2025 at 6:09:31 PM

Oh really? TIL, I thought it was dependant on the app developer. I can look into it, thanks!

by angristan

12/28/2025 at 8:55:18 PM

Hypothesis: it’s not the CPU, it’s the USB controller saturating the thermal mass.

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.

by motoboi

12/28/2025 at 9:38:35 PM

Switching which side I charge my 2019 mbp i9 effectively solved my throttling issues, so your premise might be correct as I understand it.

by scarecrowbob

12/28/2025 at 10:25:27 PM

That's interesting, could you tell me more? Like which side and port (front/back) was throttling, which side and port was not? Were you using a power supply to charge or was the mbp connected to a display? Did it only throttle during charging or also during while fully charged? Thanks!

by Coeur

12/29/2025 at 12:59:29 AM

According to a response elsewhere on this thread, it's not an unknown problem and there are links to more specific answers than I care to write. But to answer your question, it throttled with either left-side thunderbolt ports, with nothing else plugged into the machine using the Apple-supplied charger. I cannot remember if this issue stopped when the device battery was at 100%.

by scarecrowbob

12/29/2025 at 3:16:40 AM

I'm not sure if I entirely understand your hypothesis, but I don't think it's 100% on the hardware - I don't think it's due to the hardware of the hardware.

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.

by deinonychus

12/29/2025 at 5:43:43 PM

In that case, zoom is transcoding video, which is a pretty damn heavy operation (note that this is why previous MacBooks didnt have 1080p webcams: they wouldn’t stand more than 5minutes on zoom without throttling).

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.

by motoboi

12/28/2025 at 11:59:39 PM

> the body gets too hot and they lose thermal dissipation capacity for the normal usage

aka "thermal soaking"

by AceJohnny2

12/28/2025 at 5:09:23 PM

Site appears to be hugged to death, repo is: https://github.com/angristan/MacThrottle

by marksomnian

12/28/2025 at 5:42:29 PM

Oops, I fixed it, I have not very important Cloudflare Workers in front of the blog (which is on Cloudflare Pages) and somehow they were in fail closed mode and not fail open :(

by angristan

12/28/2025 at 6:49:39 PM

I have had back luck with them intermittently losing routing. Sometimes re-creating the worker fixes weird issues.

by brikym

12/28/2025 at 3:33:06 PM

You can just ping your CPU usage to the menu bar and monitor that. I have CPU and total system wattage up there so I always know if something weird is going on.

https://github.com/exelban/stats

by twilo

12/28/2025 at 3:40:45 PM

Yeah! That's how I initially suspected that it was thermal throttling because I saw in iStat Menus that my wattage was going down for a constantly high CPU usage

by angristan

12/28/2025 at 7:24:43 PM

> I know it’s thermal throttling because I can see in iStat Menus that my CPU usage is 100% while the power usage in watts goes down.

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.

by scottlamb

12/28/2025 at 9:27:23 PM

I have an M1 MacBook Air and do a once weekly virtual D&D session with some friends. I hook it up to my 4K monitor, and I assumed it had to do with that. It kept becoming a slideshow (unless I put an ice pack under it!) and I realized it’s because the battery life is so good it’s the only time of the week I charge the thing, so charging the battery was making the poor laptop a hot mess that was thermal throttling like crazy. This is with a nice dock that can push around 100W, so it isn’t necessarily an underprovisioned charger.

I started charging it an hour or two before our session, and the issues stopped.

by wincy

12/28/2025 at 10:11:47 PM

Try cabinet fans under it, will be life changing.

by j45

12/28/2025 at 7:32:16 PM

While I have definitely done this a few times, one of my MacBooks could draw more power than the power supply could deliver and there was a particular computer game that I discovered I could “only” play for about five hours before the laptop shut itself off. Because it was having to draw supplemental power from the batteries to keep up.

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.

by hinkley

12/28/2025 at 8:03:36 PM

> I know it’s thermal throttling because I can see in iStat Menus that my CPU usage is 100% while the power usage in watts goes 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?

by morning-coffee

12/28/2025 at 8:17:33 PM

My M4 Max Macbook Pro can run for a while at like 105°C and fans to the max before throttling, when it starts throttling it doesn't exceed that threshold, and then the temperature goes down for a while before throttling stops

by angristan

12/28/2025 at 7:29:00 PM

Interesting, yeah iStat Menus reports the wattage of the charger, sometimes I've charged my mac with like a 5 or 10W charger and I didn't have that issue But now that rings a bell, I think a coworker had that issue recently. I wonder why that happens

by angristan

12/28/2025 at 3:32:09 PM

There is a problem/bug with thermal pressure notifications. Did you stumbled upon such issue with your app? https://github.com/macmade/Hot/issues/73

by nazgu1

12/28/2025 at 3:38:43 PM

Ah! Yeah I did notice that using `ProcessInfo.processInfo.thermalState`, the state didn't update unless I restarted the process (reproducible even with a swift script). But this issue doesn't happen with the technique I use right now (the thermald notification)

by angristan

12/28/2025 at 3:42:41 PM

Thanks, I will check your approach. And your app as well, looks beautiful and useful.

by nazgu1

12/28/2025 at 4:37:05 PM

Thank you for the kind words :)

by angristan

12/28/2025 at 4:29:33 PM

Another thing to keep in mind with MacBook Pro models or any other device that has fans... if you have cats, dogs or other heavily shedding animals, you must regularly (for me, once a year, for people with German Shedders more like once a quarter) open them up and thoroughly clean them.

The amount of fur that manages to squeeze everywhere is insane.

by mschuster91

12/28/2025 at 4:37:22 PM

Husky/Pyr owner here - I have to systematically blow out all of my electronics because she molts enough fur to start my own Etsy brand of stuffed animals.

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).

by vunderba

12/28/2025 at 7:56:21 PM

I really wish Apple uses Vapour Chamber cooling for next MacBook Air M5.

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.

by ksec

12/29/2025 at 2:03:03 AM

Vapor chamber only helps with bursts of usage. It’s just that the heat gets transferred faster. Transferred where is the correct question to ask. To the aluminium body is the answer. Now, how much time it takes to heat that body completely (ie: to reach equilibrium with the environment) and once in equilibrium, how much joules (or watts) can the body dissipate into the environment without burning the person’s lap is the point they are optimizing for here.

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.

by motoboi

12/29/2025 at 6:34:51 AM

I am aware of that, I am of the opinion that MacBook Air provides too little time for bust usage. Or in a perfect world Apple could make the MacBook Pro super thin but with fan. Right now I think the Air is better in terms of weight.

by ksec

12/28/2025 at 5:45:30 PM

Mac fan control seems to track component temps which is pretty nice

by carterschonwald

12/28/2025 at 7:13:18 PM

Found https://github.com/macmade/Hot which works for my intel mac :)

by atymic

12/28/2025 at 10:09:25 PM

Thanks for sharing it, will try it now. I found an iMac 2017 the other day at the thrift store for $20, it’s been very good so far but will see if it throttles or not.

by tamimio

12/28/2025 at 11:01:14 PM

I’m curious why you used `@_silgen_name` to forward-declare the Darwin notification APIs. Does `import Darwin` not make them available?

by dcrazy

12/28/2025 at 11:22:07 PM

It doesn't seem like they are available with `import Darwin` indeed

by angristan

12/28/2025 at 5:04:25 PM

My 2017 macbook is basically brick. Crazy how just opening chrome sets off fans like a jet engine. How much cpu can checking gmail really use?

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.

by the_black_hand

12/28/2025 at 5:31:06 PM

The butterfly keyboard of that era was a large enough signal, to me, that high quality engineering results were compromised.

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.

by lanyard-textile

12/28/2025 at 8:46:09 PM

Yeah, 2016-2019 were severely cooling constrained unfortunately.

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!

by throwaway270925

12/28/2025 at 6:23:06 PM

I'm sorry you're saddled with an Intel Mac. The Apple Silicon Macs really changed everything. Clearly Apple is capable and willing of shipping extremely good and performant hardware, even though historically they haven't always done so. I do blame Intel for their monopoly on mediocraty for the late-10s Macbooks though.

by Arn_Thor

12/28/2025 at 7:46:51 PM

Now put Linux on it. Just like new!

by bigyabai

12/28/2025 at 9:41:31 PM

I recommend taking the bottom panel off and cleaning out dust from the fans and air ports

by dplgk

12/28/2025 at 11:22:30 PM

New thermal paste/pad might help

by newsclues

12/28/2025 at 7:44:22 PM

I hope this great tutorial encourages more developers to build native apps. Still the best development and consumer experience .

by tonymet

1/1/2026 at 1:15:46 PM

I may be mistaken - But the Hot App has been doing this for a few years if I remember correctly - In more than one way as it supports past and current architectures...

by SebFender

12/28/2025 at 6:27:51 PM

This is the type of software you hope Apple will “Sherlock” and bake into the OS!

by luxuryballs

12/29/2025 at 10:41:07 AM

Missed opportunity to use that sweating/aheago emoji

by villgax

12/28/2025 at 6:32:22 PM

neat! got it installed. thank you.

you could easily put this in the App Store (maybe?) and I'd have thrown a few bucks your way.

by gigatexal

12/29/2025 at 1:03:55 AM

Does such a thing exist for Windows?

by lloydatkinson

12/28/2025 at 3:38:13 PM

This would be a really useful thing to indicate via an unobtrusive LED on the chassis somewhere.

by rkagerer

12/28/2025 at 3:55:54 PM

Why would you take an LED over something on the screen? The notification is only really relevant while the laptop is open, and the screen is going to be on anyways.

by echoangle

12/28/2025 at 6:54:51 PM

There is no way Apple would do this on a MacBook Air, which is able to be passively cooled because of the type of use cases/users it is primarily designed for, most of whom never hit throttling. The light would only confuse almost everyone.

by alexford1987

12/28/2025 at 3:30:09 PM

brew install stats

by sys_64738

12/28/2025 at 5:11:22 PM

[flagged]

by edwardtay

12/28/2025 at 5:54:48 PM

The account that posted this comment seems to be a bot account - and one that doesn't even read the article in it's context.

by widhhddok

12/28/2025 at 6:11:29 PM

Agreed, half of these questions are answered in the post. Also, looking at the account's comment history confirms that it's karma-farming with comments or something like that

by angristan

12/28/2025 at 6:06:39 PM

One thing that annoys me about LLMs is how they say stuff that's dumb but sounds smart. For example:

> Have you considered adding historical tracking/graphing? Being able to see throttling patterns over time would be super valuable for understanding workload impacts and diagnosing thermal issues

Would it actually though? Is anyone going to ever check if their laptop was throttling at 6pm yesterday evening and then remember what they were found at that time and try to "understand workload impacts"? It's the type of thing that might come in kinda useful once in a while, not "super valuable". Idk, I notice this trend with LLMs a lot. Often what they say just doesn't really make sense when you think about it.

by ChadNauseam

12/28/2025 at 7:55:40 PM

It won't run on a MacBook Air M1 running Sonoma. Only Tahoe.

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!

by Bad_Initialism

12/28/2025 at 8:20:02 PM

I merged https://github.com/angristan/MacThrottle/pull/2 to make it work on macOS 15. macOS 14 probably works, feel free to try it out and open a PR to lower the required version if it's the case

by angristan