Some tips for anyone serious about cooling their MacBook

I wrote this up as a response to a comment about thermals in another thread (that wasn’t about thermals). But I ended up writing so much, I thought this would be better as its own discussion.

First, let’s assume you aren’t here because a rogue process is monopolizing CPU in Activity Monitor. Your Activity Monitor looks fine, yet your machine runs hot. Here’s what you can do:


  • Keep it elevated, with airflow underneath, and airflow behind, at the exhaust.
    • Even an inch underneath, at the back, helps tremendously. Like the edge of a book or a folded napkin or something in a pinch.
    • The best stand is a minimal surface area one like the Roost or this cheaper knockoff.
    • An active cooling pad with fans helps a bit. But so little it’s not worth it IMO. It’s mostly about elevating the machine.
    • A big surface that will act as a heatsink, which some laptop stands boast, is a myth. There is no thermal interface between your laptop and the stand. It won’t help you.
  • Keep your MacBook off the bed. You don’t want to insulate it.
  • Don’t keep it in clamshell mode. That messes with heat dissipation and airflow. Apple doesn’t tell you this. But Apple doesn’t tell you many of the finer foibles of their “it just works” products unless they can upsell you a magic cleaning cloth. Especially if you tax your machine for long periods with heavy tasks, don’t keep it in clamhell.
  • You may wonder whether snap-on cases and vinyl skins impact heat dissipation also. Answer: They do. But not much. Cases generally have cutouts in all the right places and are not super flush against the surface. And vinyl decals are thin. It’s worse than your MacBook’s natural bare aluminium, but go ahead and rock a case if you want, unless thermals are paramount to you for routine heavy tasks.
  • For the general thermal health of your MacBook whether you are quite concerned about thermals or not, you should monitor your temperature sensors with a tool like iStat Menus, and also set your fans a bit higher than Apple’s default, which is calibrated to maximum quietness, not maximum thermal health. For example, on my older 2015 MBP, the fans are ~2,000 RPM by default, and I switched that to 3,000 RPM. (Don’t go super high for default, because that actually will be needlessly loud, and will also wear out the bearings on the fans prematurely.)


  • Dust the inside, and the fans, with compressed gas duster like Dust-Off. Heat kills electronics. Dust is an insulator. Do this regularly if you work in a dusty environment, and do it occasionally in any case. But, don’t blow dust INTO the machine from the exhaust.
    • Again. Do not blow dust in. If you’ve already done this, don’t feel too bad, it’s not the end of the world. But it is counterintuitive. Do not do it going forward. Get yourself some pentalobe screwdrivers, take the bottom case off, and blow all the dust OUT of the machine. Although this involves screwdrivers and removing a physical component, it is as easy as a physical repair can get. No need to be shy even if you are not very “hands on” with repairs.
    • Also, when dusting the fans with compressed gas, do it in short bursts. It’s fun to hear the fans go “wheeeeeee” but it stresses the bearings unnecessarily.
  • When you have your MacBook connected to an external display, turn the internal screen off if you are not using it. And by “off”, I don’t mean the brightness. Even if you set the brightness to zero, the GPU is drawing those many millions of pixels. What you need to do is find where the hall effect sensors are on your particular MacBook model, and keep a small weak magnet or two around to trick the sensor into thinking the lid is closed (without the thermal impact of actual clamshell mode). That will properly turn the screen off and save you a lot of the overhead that causes fans to run a lot more when hooked up to external displays.


  • If your MacBook is more than a few years old, and it’s getting warmer and warmer on you, you need to replace the thermal compound. The thermal compound is a paste that conducts heat between your CPU/GPU and your heatsink. Eventually the compound dries and becomes ineffective.

    • This doesn’t require many tools. Just screwdrivers, alcohol, some lint-free cloth, and new thermal compound. But it is an advanced level repair. Take it to a tech shop if you’re hesitant.
    • If you want to try it, or already replace your own thermal compound, a tip would be to get a thicker one. Some of the most popular compounds with overclockers and thermals geeks are on the thinner side. But this doesn’t work well on laptops. Laptops have a lower clamping force than desktops between the heatsink and CPU. And if you use a thinner compound, it will pump out shortly after application. Also, do not use a conductive compound like liquid metal, for the same reason. Use a non-conductive compound that won’t damage anything if it pumps out or if you mess up while applying it.
      • Of late, some thermal pads have hit the market, to replace thermal paste. In theory the pads are everlasing. But results in terms of performance and installation success rate are kind of all over the place so far. After all, the paste works by filling the microscopic grooves between your CPU/GPU and heatsink, where they do not otherwise make contact. It is very hard to make a pad that does that. FWIW, Apple and other manufacturers still use paste.
    • Here is an 82-page thread if you want to jump into a laptop thermal paste rabbit hole.
  • A final thing I do, but is very advanced, requires a lot of trial and error to perfect, and I’m not sure whether possible on newer MacBooks, is undervolting the CPU and GPU.

    • I do NOT recommend you attempt this, even if your MacBook supports it, unless min/maxing thermals is basically your hobby. But I am including it for completeness.
    • It’s kind of like the reverse of overclocking. And unlike overclocking where you increase voltage to the CPU and GPU, when undervolting you are sending less voltage, which is wholly safe. It actually increases the life expectancy in addition to improving thermals. But, like overclocking, you have to do it in tiny increments, then stress test your machine to ensure it’s stable, sometimes for weeks per increment. Your particular CPU and GPU (not the model, but the particular units in your machine) will have their own limits. Go over those limits, and though your hardware will be happy thermally speaking, your machine will be prone to random hangs.
    • If you do want to look into it, I’d like for you to at least look in the right places, so here’s a few links:


  • Used to be a computer tech.
  • My favorite MacBook ever is the unibody 17-inch, the last of which required damn good thermal care with their glass canon GPUs.

Great suggestion on the multi monitor setup, especially if you are using an external 4k monitor with an Intel MacBook.

Could I also suggest the following as some extra ideas:

1 - If you are on a video call, keep the video window on your MacBook LCD screen, this will minimise the impact to CPU/GPU (especially with Teams).

2 - Check out Turbo Boost Switcher (, the pro version can automatically change the “boost” mode of your Intel CPU based on a number of triggers, for me I find the best triggers are fan speed (I’m more interested in excessive noise than actual temps). This can achieve some of the outcomes of fiddling with under clocking, without risk.

3 - If you have SetApp, check out Endurance that can also offer some of the capability of Turbo Boost Switcher, however requires you to turn it on manually.

For me, Turbo Boost Switcher Pro is the best answer, so I can keep my MacBook Pro (2019) screen available as extra space (and yes I have it elevated etc), whilst I notice notice my machine is a little sluggish when Turbo Boost is disabled, the benefit of relative silence is well worth it.

PS - Other folks have reported using a different Thunderbolt 3 port on your MacBook might also help, this sounds a bit random to me, but you never know with internal thermals.

May I add, if you work or live in a very dusty environment, consider a MacBook Air. Since it has no fans, there is less opportunity for dust ingress.

Love the magnet trick and for me it was a gamechanger when I connected three 4K screens to my 2019 16” MBP.

I later got a Svalt Dock to run it in clamshell mode again due to space issues no my desk

Not in my experience. I sense a clearly lower temperature on my MBP when it is on my actively-cooled fan-containing stand than when the fans are not turned on. And the stand has a substantial space between it and the laptop. So, while I agree that one cannot limit passive natural convection under the laptop, engaging forced convection can be a significant win in some cases too.

Better said … Forced convection flow from a stand with active fans will pull more heat away from the base of the laptop than will the thermal conductivity engaged by any passive heat-sink system at room temperature.


For the other 99% of people - don’t block the vents and just use your device.


For me the heat problem translates into a fan noise problem - most notably when using Webex or Skype.

Skype matters to me because that is how I record podcasts. In that case I:

  1. Record with headphones and a microphone.
  2. Place the microphone 3m across the room.
  3. Keep my broadcasting notes on an iPad next to the microphone.
  4. Use noise reduction in Ferrite when editing.