A failed experiment in laptop cooling (2025)

(kevinboone.me)

63 points | by andsoitis 4 days ago ago

72 comments

  • eigenspace 4 days ago ago

    So you say that you didn't notice the laptop temperature getting any lower, but this isn't too surprising to me, since this thing is going to be highly thermally limited.

    I suspect that your setup is doing something, but the thing it's doing is allowing your laptop to sustain a certain performance level for longer. So what I would look at is some performance metric like e.g. peakflops() in a loop, or a video game FPS counter, and compare with and without the external fans.

    • BoppreH 2 days ago ago

      The laptop fans are also targeting a set (maximum) temperature. If you provide external cooling, the internal fans will simply work less and the temperature will remain stable. So check the RPM of the internal fans too.

      • keyringlight 2 days ago ago

        Another factor is the CPU behaviour. The CPU involved in the article is intel, but IIRC for AMD Zen4 (at least for desktop) they made them boost up to a relatively high but well within spec temperature, rather than leaving performance on the table that only tweakers will see. The better your cooling capability the more you'll get but it caused a few people to freak out a little. Aspects like that are why I reserve the noisy part of my fan curve for when temperatures are going beyond normal.

        • lp92 a day ago ago

          Even Intel does the same thing. Every modern CPU does this.

    • qtqtqt 2 days ago ago

      Exactly. If you increase the capacity of a bus in a highly crowded area, the bus will still have 100% occupancy, but that doesn't mean it didn't help. The throughput increased.

      • veltas 2 days ago ago

        Much like adding an extra lane to a highway, more people will use the highway and you'll be back to the same crawl. But technically there's more flow/capacity.

        • _diyar 2 days ago ago

          Curious that you are being downvoted for the car analogy when the bus analogy you're replying to is functionally identical.

          • garretraziel 2 days ago ago

            Because it’s a slightly different argument. “More people will use the highway” is not really applicable here. The bus analogy also didn’t meant “more people will take a bus”, just that if you have bus route where 20 people on each bus stop need to wait for the next bus, if you increase capacity of buses by 10, then only 10 people will be waiting on bus stops, but you will still have 100% bus utilization.

            In other words, with added lane on highways, it’s sociological mechanism, which is slightly less precise analogy.

            • wongarsu a day ago ago

              If you run the same bus route and frequency, one day with buses that fit 50 people and have 100% utilization, and the next day with buses that fit 100 people and have 100% utilization, you transported twice as many people on the second day as on the first day

              This implies that on the first day a lot of people either didn't make their trip because there was no space, or took a different mode of transport. Presumably mostly the latter. With the highway example the same is true, just that it will be mostly people not making the trip at all before the capacity improvement because they were unwilling to make the higher time commitment

          • aaron695 a day ago ago

            [dead]

  • mnw21cam 2 days ago ago

    The little tiny fans in the laptop will typically be able to move a small amount of air with a large pressure. The fans you have used here externally will be able to move a large amount of air with a low pressure, but since you're trying to cram that air through a small space, they will actually be able to move a minuscule amount of air with that same low pressure. That's probably mostly why you aren't seeing much improvement.

    I'd say that you have two options.

    The first is to try to use external fans to force more air through the laptop than the internal fans manage. You'll need high pressure (probably centrifugal rather than radial) fans to achieve this. They'll be noisy.

    The alternative, which can use quieter low-pressure fans like the ones you have, is to just ensure that all the air going into the air intakes on the laptop is as cold as possible. That is, make sure the air going in hasn't just come out. And make sure there isn't any more restriction on air flow than the minimum possible, which the raised gap under the laptop will achieve. You basically just want to direct fresh cold air from far away from the laptop towards the air intakes, and pull the air emerging from the air outlets as far away from the laptop as possible. A horizontal breeze flowing across the bottom of the laptop is probably one of the best ways to achieve this.

  • whatever1 2 days ago ago

    We need way more of this content! Things that were tried and failed. I have spent so many head-scratching hours on problem solution approaches that others likely already tried and failed. In science we only celebrate success. Even then it is typically poorly documented.

    • spankibalt a day ago ago

      > We need way more of this content!

      Indeed, generally and specifically. Ambient temperature's gonna rise thanks to climate change; cooling solutions, especially for storage technology, need to adapt to this challenge in a fashion that also reflects economic realities.

  • pockybum522 2 days ago ago

    As is the conclusion of the article, one of the easiest things to do is simply raise the laptop more off the surface so there's less impediment to airflow.

    https://www.amazon.com/Computer-Keyboard-Anti-Slip-Compatibl...

    I was recommended these by a friend and the ability to easily do that anywhere (and as a nice side-effect get a lovely angle to the keyboard) but still be able to pop the laptop in a backpack easily is amazing. They have been put on every laptop my wife and I have owned for the last 6 years.

    • happymellon 10 hours ago ago

      Similar concept, but I have this as it folds into a smaller size for backpacks.

      https://www.amazon.co.uk/dp/B01D52MWF0

      The one drawback is that it really shows off how bad the angle on the Macbook is when the laptop is raised up compared to other manufacturers.

  • Tade0 2 days ago ago

    So close to greatness.

    I've dabbled in this and the one thing that absolutely has to be included is a seal on the edges between the laptop and the stand like so:

    https://www.ebay.com/itm/126317216434

    Otherwise the air will escape to the sides.

    For my home project I used foam tape, but any seal will do.

    Regarding cooling I wholeheartedly recommend one Framework 16 owner's journey in making his device maintain 80°C with the CPU going full throttle (aside from other mods):

    https://community.frame.work/t/all-the-modifications-ive-mad...

    • vintagedave 2 days ago ago

      > Otherwise the air will escape to the sides.

      Don't you want it to do that? The air goes upwards, hits the laptop surface, and travels outwards carrying the heat?

      If it's sealed, I imagine you would get a very turbulent situation, possibly far noisier, but also one where I can't intuitively picture the airflow and expected cooling flow. I should note I am very, very far from an expert here ;)

      • Tade0 2 days ago ago

        There's a lot going on here, but the gist is that even a magnesium alloy laptop chassis is a rather poor conductor of heat (for a metal) and you really have to push that air through the machine to get it out.

  • turbocon 2 days ago ago

    So I had a similar problem and what actually worked pretty well was an external vacuum fan [1]. I tested it before by just using an inflator I had to pull a vacuum and I watched the CPU temp drop so I knew this was valid.

    [1] this is just example, there's better ones I'm sure. https://www.amazon.com/KLIM-Tempest-Laptop-Cooler-Vacuum/dp/...

  • drbig 2 days ago ago

    Compact electronics rarely have vents "close" to the things that get hot - it's been heat pipes for a long time already; and that system is fixed and "scaled" for the included fan(s)... Not much anyone can do in practice without taking the laptop apart - at which point you'd be better off buying a (mini) PC in the first place.

    Also: thermals in general are vastly more complex and tricky than our intuition tends to tell us (with the article being a great example of it!).

  • schobi 2 days ago ago

    Well - the challenge is with the right type of fans.

    I like the idea of a pump curve for a garden water pump. If you pump water without any back pressure (not even a hose connected), the pump will give a certain volume per time that is can move. If you connect a hose and pump upwards, you will reach a max pressure / max height at which no water will flow any more. Both cases are useless, but this is what the manufacturer prints on the box. Your sweet spot is in between. If you pay enough, you will get a datasheet with the pump curve in between these two points.

    For simple and cheap PC fans, you are at most given the number of air volume without back pressure. I've not come across a cheap fan that gives a defined backpressure of even a curve.

    For your application you would need a fan that can push air through a restriction.

    I had success with high rpm server fans. They create pressure, consume 20W of power or more and also make a lot of noise. But in this case - this is not a solution

  • fwlr 2 days ago ago

    Probably a monster chip like that has way more headroom than you expect, and can max out the extra cooling you’re giving it as well. If the goal is to avoid the 90C blast, maybe enabling thermal throttling plus using the custom cooling setup will give you (much?) less of a drop in performance than throttling with stock cooling?

  • edding4500 2 days ago ago

    Just a note: some laptop fans are not solely controlled by CPU or GPU temperature, but also by power consumption. This may explain why your laptops internal fans are still spinning up under load, even though the external fans do all the work already.

  • lp92 a day ago ago

    You'd be surprised by how much of a difference just cleaning the fans and applying new TIM will do. Preferably using a quality phase change TIM like those from Honeywell or Laird will work very well on devices like this.

    I actually replaced the stock Liquid Metal on my ASUS Zephyrus with some Laird PCM and hot spot temps actually evened out towards the lower end and the low/high/average temps were the same after around a week or two of thermal cycling.

  • xnickb 2 days ago ago

    I drilled some holes in my Framework laptop's bezel.

    It isn't designed to be used with the lid closed which is what I do 99% of the time. After drilling the performance with the lid closed went up 30%, with the lid open up 5%. Removing the bezel with the lid open gives extra 10% vs normal bezel.

    The nice thing is these can be swapped easily (magnets) and come in different colors. I used to have 2 until I stopped caring about my laptop looking weird in public.

  • ozim 2 days ago ago

    Seems P53 has plastic chassis, I bought fan stand for my laptops that have metal chassis because that is used as heat sink. With metal you don’t need magically placed fans you just want to cool the surface.

    For overpowered CPU that should not be in laptop it won’t help anyway, I had core i9 and best thing to do was to sell it and just swap to core i7 because there was no home made trick to make it better even with metal chassis.

  • Choad_20261104 a day ago ago

    If you have some extra $$$ (on the order of $250), you could start buying TE coolers. When I was an undergrad long ago, in my internship job we were cooling a focal plane on a satellite using some TE coolers [electracooldotcom] from the precursor of this company.

    OR maybe try immersing the unit in ampcool or bitcool [engineeredfluidsdotcom] (again around $250) and use a recirculating pump from a fish tank and some clever piping into the hot parts inside the case of the laptop then out over a decorative waterfall to bleed off the transferred heat from the PC into the environment

    • nicd a day ago ago

      Thermoelectric coolers are an interesting technology, but have fairly poor efficiency. Plus, you still need somewhere for the heat to go (which probably still means heatsink + fans).

      A thermal engineer I know remarked that non-thermal engineers often suggested TECs, and her job was pointing out why they are rarely the right tool for the job.

      • Choad_20261104 4 hours ago ago

        yeah. It was a hail mary for the guy. Honestly the a immersion is better bet but it is kind of messy - not gonna got have some toast at the breakfast table with that laptop after that

  • ummonk a day ago ago

    > at full load my P53’s CPU runs at ~90°C, regardless of the cooling, regardless of positioning. It never runs any hotter than that, which I presume is because that’s the point at which it’s throttled.

    Shouldn't the author be measuring whether the amount of throttling changes when on the stand? The stand could be causing a significant improvement without fully eliminating the throttling (which would be needed to see a temperature drop as the author expected).

  • Someone 2 days ago ago

    FTA: “In the end, I’m not really sure we can just put dissimilar fans in series. If you put a fan that can pump (say) 200 cubic feet per minute (CFM) in series with a fan that can only pump 100 CFM, what is the resulting output? Probably not 300 CFM.”

    “Dissimilar” isn’t needed there.

    https://www.rotron.com/Resources/Application-Notes/Series-an...:

    “When applying more than one fan in a system:

    - "n" fans in series will increase pressure "n" times at a given flow rate, with no additional free delivery flow. Fans in series can be useful in high resistance systems.

    - "n" fans in parallel will increase flow "n" times at a given pressure level, with no additional shutoff pressure generated. Fans in parallel can be useful in low resistance systems.”

  • rickdeckard 2 days ago ago

    I'm not surprised that this doesn't change the CPU temp.

    The important heat-exchange from the CPU is usually managed by a heatsink and a radial fan, with the grille of the casing designed as fan inlet/outlet.

    Blowing/sucking additional air at the inlets doesn't affect the cooling surface of the heatsink, it just blows at the radial fan.

    This may make sense if there's a weakness of the radial fan (that heat is building up at the heatsink which the original fan cannot remove).

    But it's much more likely that the heat is not distributed well away from the CPU, either to the heatsink (thermal paste) or by the heatsink (weak heatsink design/material).

    I'd look into ways to replace the radial fan or the thermal paste

  • nukanse 2 days ago ago

    I got a laptop cpu in a desktop motherboard (a mini PC board). It was cheaper, and performs much better that the same cpu in a laptop. It was a steal. It's like shucking an hdd, an incredible value for the price.

    • shellwizard 2 days ago ago

      A frankencpu BGA to LGA? I am aware they're sold in places like AliExpress, but in addition to it you need to flash a custom BIOS in order to post.

      • 2 days ago ago
        [deleted]
      • bajard 2 days ago ago

        I got one from Amazon. A 32-thread Ryzen 9 7945HX, along with a motherboard, CPU cooler, case, and PSU for $400. But I didn't trust the PSU, so I bought a better one, replaced the thermal paste with PTM 7950, and replaced the CPU fan with a Noctua.

        I also had to buy SODIMM DDR5 RAM modules (just before prices skyrocketed, I got 64 GB for $180), a 2 TB Samsung NVMe SSD, and an RTX 5060. The CPU comes with an integrated GPU, but I disabled it to get better cooling.

        I also wanted to replace the CPU cooler with a Noctua one, but the GPU sits too close to the CPU. Maybe someday I'll adapt a liquid-cooling radiator, but that would require 3D printing a custom adapter and making multiple trips to a 3D printing shop for trial and error. That's too much hassle.

  • yread 2 days ago ago

    It's a pity laptop manufacturers haven't figured out how to dissipate heat by using the lid as radiator. I read about some experiments years ago where they managed to get rid of like 25W

    Edit: yes, normal laptop with all the bits under the keyboard and heat pipe going to the lid. I can't find a better source than this patent

    https://patents.google.com/patent/US5880929A/en

    But I distinctly remember seeing photos of a prototype in something like wired or the register

    • skandinaff 2 days ago ago

      Interesting, were those experiments with traditional layout when motherboard is in the bottom part of the laptop? Maybe we just need to make screen heavy laptops with thin keyboards but with thicker cooling, that could also utilize convection better. Something that you put vertically and open keyboard down, I think some gaming tablets are like this now

      • lp92 a day ago ago

        You can use a thermal strap to transfer heat through the laptop hinges and in to the top screen area. This kind of technique is used in aerospace and other industrial applications to transfer heat from unusual places.

        But trying to do this on a laptop introduce thermal issues for the screen. LCD/OLEDs are rather heat sensitive. OLEDs especially do require good heat sinking for the performance and display life.

        Edit: I realized many people might not have heard of thermal straps. Here's a quick read: https://www.techapps.com/thermal-straps with quite a few pics/examples.

    • fmajid 2 days ago ago

      The displays generate their own heat

    • pockybum522 2 days ago ago

      That is so extremely cool (ha) but boy, that sounds difficult to make reliable through ~100,000 lid open/close cycles. Still, I would love this if it could be made so. I have seen so many horror stories of "I'm using my laptop in my lap on a blanket and blocking all the cooling, why is it so hot?"

  • tapland 2 days ago ago

    Raising it is the most important part. After that, if you can pop the bottom off while it's running, and swapping out the thermal paste are my go-to.

  • PowerElectronix 2 days ago ago

    If I had a penny for every time a heat engineer's suggestion was discarded because it's too expensive, too time consuming to implement this late into the project or too impactful on weight or size I'd be rich already. The only guys I know that are ignored more than them are the EMI filter designers ("what's EM noise anyways?")

  • origini 2 days ago ago

    CPUs control frequency themselves and throttle. No need for manual throttling.

    And it also might be a problem with the cpu paste and not with air.

  • bajard 2 days ago ago

    Frore makes thin flat electrostatic coolers that would be perfect for laptop SSDs, but I don't know if they're available for purchase by consumers.

    The main problem would be powering them. They could potentially draw power from the M.2 connector through an adapter, or soldering to an USB connector, I guess.

    • lp92 a day ago ago

      There's a few OEM units using their tech, but largely not still available in the market. Im honestly surprised they haven't been able to convince a high end OEM tp get them in to their laptop line.

  • veltas 2 days ago ago

    Amazing they're called 'laptops' when you haven't been able to safely keep a laptop on the top of your lap for decades.

    Even slight increases in temperature is enough to do damage to certain parts of a man, and it's really not good for your legs to have this extremely hot air blasted over it continuously.

    • martheen a day ago ago

      Are they ever safe? Aside from Atom and maybe the AMD equivalent, they've always been hot when not idling. And those Atoms are so tiny you might as well just hold them in your hand

  • progval 2 days ago ago

    How feasible would it be for laptop manufacturers to add a slot in a laptop's underside cover to the CPU's heat pipe, and adjust the heat pipe's shape at this location? This would allow a dock to insert its own heat pipe through it, and dissipate the heat with larger fans and/or larger heat sink.

    • electroweak a day ago ago

      An excellent idea. There's a certain class of laptops that were never meant to be used on one's lap- at best merely portable e.g. Dell precision specced at 240w.

      If the pad contact locks together for heat transfer it could also function as a security lock.

      The dock could have a water cooling loop under your desk to dry your boots while you work.

    • jpalomaki 2 days ago ago

      For Macbook Air there was DIY solutions where people added thermal pads to conduct the heat to the aluminium chassis and then use external cooling on that [1]. Since Air just has passive cooling, this gave major boost for long running tasks.

      [1] https://forums.macrumors.com/threads/guide-macbook-air-heats...

    • mrheosuper 2 days ago ago

      It would risk the user touching the heatpipe during work, which is quite toasty under heavy load.

    • gambiting 2 days ago ago

      Not quite the same, but there are laptops with external water cooling that connect to internal piping inside the laptop when placed on the dock:

      https://videocardz.com/newz/colorful-launches-water-cooled-l...

  • gus_massa 3 days ago ago

    > I picked the locations of the fans and their supports very carefully, and it’s clear that the intakes aren’t blocked.

    Just double checking: Did you put the fans in the correct orientation and on the intakes instead of the exits?

  • musha68k 2 days ago ago

    The mobile hardware edge that Apple still holds on almost every front still seems substantial.

    I wish there would be only one company that could seriously meet them at their functional high ground.

  • tniemi 2 days ago ago

    I'm using the Ikea Drönjöns laptop stand. It is made of metal so it conducts heat to wider area. That is probably more important than some extra fans.

  • patates 2 days ago ago

    Totally noob question: Couldn't the problem just be that the laptop body not conducting heat so much? I think it'd be worth to try it with a macbook.

  • mrheosuper 2 days ago ago

    Aren't those laptops designed to boost until it hits the max temp ? OP should test performance before and after.

  • deepsun 2 days ago ago

    Another thing author missed is thermal paste. I got way better cooling in my 2-year old framework by just replacing the dried out paste.

    • rast1234 2 days ago ago

      or even better a PTM. i was battling high temps and stutter due to throttling on my lenovo legion with ryzen 7945hx. stock thermal compound, whatever it was, didn't cut it. regular thermal paste was slightly better. PTM finally fixed it even to a point when i can use unlimited power mode.

      for half a year at least, until radiators get clogged with dust and thing requires total disassembly. i'm looking to add metal mesh as filter, see how that works

  • khalic 2 days ago ago

    keep going, it's just one negative result, try to model the airflows and heat transfers in your mind, etc.

  • avazhi 16 hours ago ago

    Those specs wouldn’t even qualify as a mid tier workstation. Not saying laptop cooling is sufficient, but you’d have to go back to 2010 to find high end workstations with comparable specs.

    My sandy bridge from like 2011 was what, 3.2GHz base with 6 cores? And a 1070 has 8GB of VRAM.

    You could keep that machine at 60C and you still wouldn’t get 1/3 of the performance of a modern high end workstation.

  • theodric 2 days ago ago

    Back during COVID I had an old MacBook Pro that I was using as a desktop which would run its fans at full blast whenever I had to do a video call, which was a lot of the time. Since I no longer had any intention to use this device as a laptop, I decided the best course of action would be to try and get as much heat into the metal baseplate of the laptop as I could, and then draw that heat off by some means. I settled on using large water cooling plates intended for Bitcoin ASIC miners. It worked really well! I posted about it on MacRumors: https://forums.macrumors.com/threads/so-i-water-cooled-my-ma...

    • maurits 17 hours ago ago

      My late mac book air used to spend its summers on a wrapped bag of frozen pees.

  • vconnor 2 days ago ago

    This blog has been very popular lately. 12 submissions in the past 3 days.

  • compsciphd 2 days ago ago

    wouldn't one need high static pressure fans for this to work?

  • chaostheory 2 days ago ago

    I’ve had some mild success with external piezoelectric coolers. However, the form factor isn’t ideal (weird angle, which led to a lot of returns from other people, so it’s no longer on Amazon)

  • redanddead a day ago ago

    wake me up when you try something fun and risky like a liquid cooled laptop

  • jttnr 2 days ago ago

    [dead]