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How to control Mac fan speeds manually

Apple doesn’t open up its hardware to users or developers very easily. This goes for most of its hardware; desktop, TV, and phones. On the desktop though, it can’t be as restrictive as it might like e.g., you can install apps from outside the Mac App Store with little to no effort which is something you can’t do on an iPhone.

On a Mac, any type, you can control the fan speeds manually. Apple doesn’t give you a tool to do it but there are third-party apps that you can use. Here’s how you can control Mac fan speeds manually.

Control Mac fan speeds

Before we proceed, you should know that this isn’t something you should take lightly. The fan(s) keeps a Mac cool and if it overheats, for whatever reason, it can damage the hardware. The damage may not be covered by any warranty that you have so be careful.

Macs Fan Control

To control the fan speed, download an app called Macs Fan Control. Make sure you move the app to the Applications folder before you run it. You’ll see the following interface. The number of fans that you see will differ based on the Mac model you’re using. Some Macs have three fans, others only have one.

Sensors

You will also see a list of sensors in the column on the right. These are the sensors that can measure temperature which will be instrumental in how you change the fan speed.

Fan RPM

One final thing you should know is that fan speeds are set in RPM i.e., rotations per minute. Higher RPM means the fan runs faster, and lower RPM means it runs slower.

To control a fan’s speed, run the app and follow the steps below;

  1. You will see all the fans that are on your Mac. Note the Min/Current/Max values for a fan. These are RPM values.
  2. Select a fan and click the ‘Custom’ button next to it.
  3. There are two ways to control the speed of a Mac; RPM, and sensor based. In the panel that opens when you click ‘Custom’, the RPM option is selected by default. With RMP, you have to enter a value but the value will have to be within the Min and Max values that you noted in the first step.
  4. If you don’t want to use RPM values to determine the speed, you can set it to be temperature based. Select the Sensor-based option.
  5. You will see a dropdown that will list the sensors on your Mac. The speed of the fan can be set to the temperature of the sensor you select. Choose one from the list, and set a minimum and maximum temperature that will trigger the fan to run or run faster. Click OK.

Troubleshooting fans

While this is generally safe, you can run into problems with the fan even if you aren’t changing how they work. If your fans are suddenly running when they shouldn’t, running constantly, or not running at all, you’re going to have to fix it. To fix it, you have to perform an SMC reset or a System Management Controller reset.

Desktop Mac/iMac

  1. Shut down the Mac.
  2. Unplug it.
  3. Wait for 15 – 20 seconds.
  4. Plug it back in.
  5. Wait another 5 seconds.
  6. Turn the Mac on.

MacBooks

  1. Shut down the MacBook.
  2. Do not disconnect the power adapter. If it isn’t connected, connect it first before moving to the next step.
  3. Hold down the Left Shift key + Control + Option + Power button all at once for 15 seconds.
  4. Release the buttons and wait 5 seconds.
  5. Tap the Power button to turn the MacBook on, and your fans should be back to normal.

Managing heat and fans

If you have a single fan on your Mac, it might be fairly simple to manage it since you know it’s the only thing that will be keeping it cool. If you have more than one fan though, it means cooling is divided between them and you will have to look at several different regions within the chassis of the Mac to manage the heat effectively. With multiple fans, it is also possible that a single fan doesn’t have access to all the sensors on your Mac in which case you’ll have to keep an eye on multiple sensors and the temperature of multiple regions. It’s not easy and it’s a good idea to research how heat flows in your Mac model before you proceed.

Conclusion

Macs generally do a good job of managing how hot or how cool they run. You won’t often hear of a Mac shutting down because it overheated while the same cannot be said for a Windows PC. Macs are also not used for gaming but they are often the go-to system for design and animation and those apps do tend to run the Mac hot so it might help to know how to manually manage the heat on it. If your Mac is running too hot all the time, and it doesn’t have anything to do with your apps, consider taking it in for a check.

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