By default, Apple automatically runs your Mac's fans without configuring them. If your system gets too hot, the fans will start up. Manually control your fans with the free Macs Fan Control app. There are two reasons why you want to do this: to make your Mac run faster, but louder or slower, but quieter. Apple's automatic control targets somewhere in the middle.
Your Mac throttles your CPU if it gets too hot and slows it down considerably until the temperature is under control. Usually this will happen before the temperature gets too high. However, you can continue to manually press the CPU by setting the fan speed higher than Apple normally allows. That makes a lot of noise, which is why the automatic control tries to slow them down.
If you hate fan noise, you can turn it off manually. Keep in mind that this will make your system much hotter and lead to system instability if you let it go too far.
Both options should monitor the temperature of your CPU and other components and make sure that you do not cause any damage to your system. It is also possible that running fans for a long time at maximum speed can cause damage. Try not to torture your laptop.
Controlling the Fans
Start by downloading the Macs Fan Control app and moving it to the Applications folder. At startup, you'll see a list of all fans and the option to set custom controls. Auto retains the default behavior, but opening Custom allows you to set a specific RPM or target temperature.
Sensor-based value optimization mimics automatic behavior, but lets you choose how hot your system should be. You can increase the maximum temperature if you want more power, or lower if you want your fans to be quieter.
As a nice touch, the App also lets you monitor the temperature sensors in your system. The most important are the CPU core temperatures.
If the application does not need to be opened constantly, you can set one of the fans and sensors for the display menu bar with the app icon; Click on the "Preferences" button in the lower right corner to access these settings.
This adds a nice sensor in the menu bar and does not take much space when you view it two lines.
In the General Preferences, you can also start the application at startup and display temperatures in Fahrenheit.
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