# How does Apple cool their computers? **URL:** \ **Category:** Factual Questions\ **Created:** [June 9, 2017, 2:57am UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477 "2017-06-09T02:57:48Z")\ **Posts on this page:** 17\ **Page:** 3
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [June 15, 2017, 3:23pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/41 "2017-06-15T15:23:05Z")
> [@Jophiel](#): > > Granted, my CPU is overclocked but my main reason for moving from air to water was to decrease noise from all the fans (by eliminating them, naturally). There is also a major disconnect in what people believe is “air cooled” All modern laptops and most desktops use heat pipes, which are closed loop evaporative thermal transfer devices. While I am not sure what chemical they are using as a working fluid but it is probably more appropriate to call a modern laptop as something like “passive acetone cooled” to compare to “active water cooled”. The thermal conductivity of metals is way to slow and the heat sinks would be way too huge to not use a heat pipe like solution. The air side radiator still has the same limitations based on air temp, air volume and air speed for that radiator. ---
**Author:** ![TimeWinder](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@TimeWinder](https://boards.straightdope.com/u/TimeWinder)\ **Post date:** [June 15, 2017, 3:33pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/42 "2017-06-15T15:33:53Z")
I’m working on (a previous generation) one right now, and was running a high-CPU brute force password cracker overnight (I’m not a hacker – we lost the password to some components because of lack of planning). The fans came on a couple minutes after I maxed out the cores, and ran constantly until the app ended. The front of the system is fine, but the back is unpleasantly warm to the touch – I think one thing missed above is that most of the entire aluminum body can act as a heat sink, and apparently does. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [June 15, 2017, 3:49pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/43 "2017-06-15T15:49:09Z")
> [@TimeWinder](#): > > I’m working on (a previous generation) one right now, and was running a high-CPU brute force password cracker overnight (I’m not a hacker – we lost the password to some components because of lack of planning). > > The fans came on a couple minutes after I maxed out the cores, and ran constantly until the app ended. The front of the system is fine, but the back is unpleasantly warm to the touch – I think one thing missed above is that most of the entire aluminum body can act as a heat sink, and apparently does. As far as performance and throttling goes the metal body is actually a limiter than an advantage in this case 😃 Apple has to reduce power consumption, thus performance to keep temperatures below safe touch temperatures, and the retained heat warms the incoming air and dramatically reduces it’s cooling potential and the fans ability to move air. It does work as a good buffer and reduces how often the fan does need to be run at high speeds on bursts though which leads to a quieter computer for most users. We actually tested a plastic replacement for the MacPro and it resulted in a significant performance increase in sustained tasks (Our compile and tests too 1.5 hours) but was financially unworkable and the precision of the machining required prevented us from applying less thermally conductive coatings. The fairly reliably sourced but still rumor was that the old towers no longer met international regulations due to exposed wires and were discounted due to that reason. Apple just chose to not manufacture a replacement system. For most of their consumer base this isn’t critical, but for those of us who try to comply with their EULA have been dealing with this for years now. Internally apple just uses COTS linux machines as they are not limited by their own EULA. Edited to add it appears that the heat pipes in laptops use water, so they are technically passively water cooled. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [June 15, 2017, 4:08pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/44 "2017-06-15T16:08:29Z")
Sorry about paying attention to content and not spelling in that past post, s/discounted/discontinued as an example. But Apple decided that size and aesthetics was more critical to their consumer base, this seems to have been a good bet looking at their marketing share, but if performance is critical a thicker, plastic cased system like a Lenovo P50 will have better performance just due to the thermal constraints even with the same major components. Apple did force PC manufactures to up their material qualities but they are using the same commodity parts everyone else is, and as almost all laptops are produced by three global ODMs there is little in engineering team differentiation. It is purely market segment, price point and what compromises the companies chose to make to try and attract consumers. A Macbook pro, Lenovo Yoga or other devices will be limited by their thermals, and while some modern features like logical processor idling, improved speed stepping and reduced feature size chips help you really just have to go back to a laptop or desktop designed for the workstation market if sustained performance is critical to your needs. FWIW, even with rackmount servers thermals are the limiter and in a raised floor datacenter the systems closer to the floor will run faster as they have cooler inlet air. This is what “turbo” mode is on a CPU, it can exceed the rated power for the package until the heat rises too much at which point it has to throttle. In modern Intel CPUs the steady state can actually be below the rated clock speed depending on what instructions are being used. As an example when using AVX instructions on all cores a Xeon e5-5690 will run at around 2.1Ghz where it can run at almost 3.2 Ghz just using integer math if it has proper cooling. For systems with enough airflow it is the chip temperature which is the limit, in ultra-portable metal bodied laptops or all in ones it is the touch pain threshold. ---
**Author:** ![Jophiel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jophiel/32/66_2.png) [@Jophiel](https://boards.straightdope.com/u/Jophiel)\ **Post date:** [June 15, 2017, 4:09pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/45 "2017-06-15T16:09:34Z")
> [@rat\_avatar](#): > > There is also a major disconnect in what people believe is “air cooled” All modern laptops and most desktops use heat pipes, which are closed loop evaporative thermal transfer devices. > > While I am not sure what chemical they are using as a working fluid but it is probably more appropriate to call a modern laptop as something like “passive acetone cooled” to compare to “active water cooled”. > > The thermal conductivity of metals is way to slow and the heat sinks would be way too huge to not use a heat pipe like solution. The air side radiator still has the same limitations based on air temp, air volume and air speed for that radiator. I’m not sure I’m following. Are you saying that the popular [212 EVO cooler](http://www.coolermaster.com/cooling/cpu-air-cooler/hyper-212-evo/) has liquid in the copper heat pipes? The old [stock Intel heatsink](http://www.hardwaresecrets.com/wp-content/uploads/ictc011.jpg)/fans obviously don’t (they don’t even have pipes). I’m using what most people (I assume) would consider [a liquid cooler](http://www.corsair.com/en-us/hydro-series-h100i-v2-extreme-performance-liquid-cpu-cooler), where there is a fan/air component to cooling the radiator but the use of liquid makes the heat transfer off the CPU much more efficient. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [June 15, 2017, 4:39pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/46 "2017-06-15T16:39:15Z")
> [@Jophiel](#): > > I’m not sure I’m following. Are you saying that the popular [212 EVO cooler](http://www.coolermaster.com/cooling/cpu-air-cooler/hyper-212-evo/) has liquid in the copper heat pipes? Yep. That’s what [heat pipes](https://en.wikipedia.org/wiki/Heat_pipe) are. You basically have one of those little glass bobbing birds on your CPU. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 15, 2017, 4:43pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/47 "2017-06-15T16:43:00Z")
> [@Jophiel](#): > > I’m not sure I’m following. Are you saying that the popular [212 EVO cooler](http://www.coolermaster.com/cooling/cpu-air-cooler/hyper-212-evo/) has liquid in the copper heat pipes? Yes, that’s exactly what a [heat pipe](https://en.wikipedia.org/wiki/Heat_pipe) is. It’s different from a liquid cooling system though. A heat pipe relies on phase change (evaporation) to carry the heat; the working fluid evaporates at the CPU end, carrying heat to the other end where it is cooled by the heatsink/fan and condenses. The condensed liquid is carried back to the CPU end by a wick (capillary action). A liquid cooler does not use phase change. The cooling liquid stays liquid, and carries away heat by forced circulation (i.e. moved by a pump). I’m not sure if stock Intel CPU coolers use heat pipes though. But most aftermarket coolers do. And most laptops. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [June 15, 2017, 5:01pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/48 "2017-06-15T17:01:29Z")
> [@scr4](#): > > I’m not sure if stock Intel CPU coolers use heat pipes though. Looks like Intel doesn’t, but AMD does. Look midway down [this](http://techreport.com/review/23624/how-to-build-a-pc-the-tech-report-guide/3) page. My stock AMD sink looks more or less like that one. (And _holy crap_ on that Corsair!) ---
**Author:** ![Madmon](https://avatars.discourse-cdn.com/v4/letter/m/cdc98d/32.png) [@Madmon](https://boards.straightdope.com/u/Madmon)\ **Post date:** [June 15, 2017, 5:09pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/49 "2017-06-15T17:09:02Z")
they might have a lot of fans on there macs ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 15, 2017, 5:13pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/50 "2017-06-15T17:13:16Z")
> [@Darren\_Garrison](#): > > Looks like Intel doesn’t, but AMD does. Look midway down [this](http://techreport.com/review/23624/how-to-build-a-pc-the-tech-report-guide/3) page. My stock AMD sink looks more or less like that one. (And _holy crap_ on that Corsair!) I use a Noctua cooler on my Hackintosh which is very similar to that Corsair. It’s very quiet, due to the two large fans (the larger the fan, the quieter it is for a given volume of air moved). ---
**Author:** ![Jophiel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jophiel/32/66_2.png) [@Jophiel](https://boards.straightdope.com/u/Jophiel)\ **Post date:** [June 15, 2017, 5:51pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/51 "2017-06-15T17:51:18Z")
> [@Darren\_Garrison](#): > > Yep. That’s what [heat pipes](https://en.wikipedia.org/wiki/Heat_pipe) are. You basically have one of those little glass bobbing birds on your CPU. > [@scr4](#): > > Yes, that’s exactly what a [heat pipe](https://en.wikipedia.org/wiki/Heat_pipe) is. Interesting. Granted, it was nothing I ever put much thought into but if anyone had asked I would have guessed not. Thanks. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [June 15, 2017, 5:55pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/52 "2017-06-15T17:55:38Z")
> [@Darren\_Garrison](#): > > Looks like Intel doesn’t, but AMD does. Look midway down [this](http://techreport.com/review/23624/how-to-build-a-pc-the-tech-report-guide/3) page. My stock AMD sink looks more or less like that one. (And _holy crap_ on that Corsair!) It depends on the TPD, but in the case of all-in-ones or laptops most intel SKUs will require it for a sell-able size. Note that post skylake the higher TPD CPUs no longer come with the boxed fans and they do have heat pipe solutions. but this document will show the requirements, but outside of the fact that they use good ball bearings in the fan the PGC 2013D fan just really doesn’t care about noise. but that only works if you are following the ATX spec closely and have enough airflow which is also covered in the following specsheet. [https://www.intel.com/content/www/us/en/processors/core/4th-gen-core-family-desktop-tmsdg.html](https://www.intel.com/content/www/us/en/processors/core/4th-gen-core-family-desktop-tmsdg.html) One of the big reasons to use heat pipes and passive evaporative cooling is that the recovery time is significantly shorter where heat soak on those inexpensive coolers will take much longer to recover. While Intel doesn’t really share the throttling data on the desktop chips they do on their Xeons and you can see the effects of AVX and core useage on turbo here > **[Knowledge Center Archives - Microway](https://www.microway.com/category/knowledge-center-articles/)** ---
**Author:** ![Cornelius\_Tuggerson](https://avatars.discourse-cdn.com/v4/letter/c/13edae/32.png) [@Cornelius\_Tuggerson](https://boards.straightdope.com/u/Cornelius_Tuggerson)\ **Post date:** [June 15, 2017, 6:20pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/53 "2017-06-15T18:20:50Z")
Not really about apple, but I am really looking forward to [this](http://www.calyos-tm.com/calyos-fanless-pc-workstation/) thing. No fans, no water, just a giant external heat sink and a closed loop of magic cooling liquid for the processor and gpu. Linus did a demo of one a while back and it looked simple, quiet and awesome. ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [June 15, 2017, 8:11pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/54 "2017-06-15T20:11:03Z")
> [@scr4](#): > > Yes, that’s exactly what a [heat pipe](https://en.wikipedia.org/wiki/Heat_pipe) is. > > It’s different from a liquid cooling system though. A heat pipe relies on phase change (evaporation) to carry the heat; the working fluid evaporates at the CPU end, carrying heat to the other end where it is cooled by the heatsink/fan and condenses. The condensed liquid is carried back to the CPU end by a wick (capillary action). > > A liquid cooler does not use phase change. The cooling liquid stays liquid, and carries away heat by forced circulation (i.e. moved by a pump). At least, if you’re doing it right. :eek: I frankly would love to see a youtube video of an overclock that actually turns liquid cooling into pressurized-steam cooling. 😃 ---
**Author:** ![Jophiel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jophiel/32/66_2.png) [@Jophiel](https://boards.straightdope.com/u/Jophiel)\ **Post date:** [June 15, 2017, 8:23pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/55 "2017-06-15T20:23:33Z")
If the heat pipes work by liquid coming down to the CPU end, wouldn’t a ‘tower’ style setup like the linked Corsairs work terribly? They’re usually [installed horizontally](http://cdn.overclock.net/2/20/900x600px-LL-202f1489_100_0592.jpeg) so the liquid would be resting on the “bottom” of the pipes, not coming in contact with the CPU end. In fact, it seems as though [half the pipes](https://images10.newegg.com/BizIntell/item/35/103/35-103-065/hyper212p_001_update.jpg) will end in an uphill climb for the settling liquid in a horizontal setup. ---
**Author:** ![Jophiel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jophiel/32/66_2.png) [@Jophiel](https://boards.straightdope.com/u/Jophiel)\ **Post date:** [June 15, 2017, 8:29pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/56 "2017-06-15T20:29:06Z")
Too late to edit but, that second photo shows more of a “U” setup to the pipes but some seem much [more crimped](https://images10.newegg.com/BizIntell/item/35/103/35-103-099/hyper212_001.jpg) at the CPU end. They might still allow passage all the way through the pipe. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [June 15, 2017, 8:35pm UTC](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477/57 "2017-06-15T20:35:26Z")
> [@Jophiel](#): > > If the heat pipes work by liquid coming down to the CPU end, wouldn’t a ‘tower’ style setup like the linked Corsairs work terribly? They’re usually [installed horizontally](http://cdn.overclock.net/2/20/900x600px-LL-202f1489_100_0592.jpeg) so the liquid would be resting on the “bottom” of the pipes, not coming in contact with the CPU end. In fact, it seems as though [half the pipes](https://images10.newegg.com/BizIntell/item/35/103/35-103-065/hyper212p_001_update.jpg) will end in an uphill climb for the settling liquid in a horizontal setup. They use sintered powered metal or wicks, the liquid is in the entire length of the wick until if phase changes to a gas. When it is cooled and returns to a liquid state it condenses on the walls where this wick is. Basically they entire inside surface is a tube shaped wick. This video will demonstrate it better than text [![](https://img.youtube.com/vi/2vk5B6Gga10/maxresdefault.jpg "Heat Pipe Basics and Demonstration Video") ](https://www.youtube.com/watch?v=2vk5B6Gga10) [Previous page](https://boards.straightdope.com/t/how-does-apple-cool-their-computers/788477.md?page=2)