Some Apple products contain sensors that respond when they detect temperature changes inside your system or device, turning on fans to bring cooling airflow to critical components.
About fan noise
If your device's processor is working on intensive tasks — such as compressing HD video, playing a graphics-heavy game or indexing the hard drive with Spotlight after you've migrated data — the fans run faster to provide additional airflow. You may hear fan noise when this is happening, especially if you're in a quiet environment. This rushing-air sound is a normal part of the cooling process.
Ambient temperature, the temperature outside the device, also plays a role in the fans' responsiveness. If the ambient temperature is high, the fans turn on sooner and run faster. Find out more about the operating temperature of Apple notebook computers.
Make sure the vents on your Apple product aren't blocked
Some Apple products have vents that let fans bring in cool air and expel hot air. Make sure the vents aren't blocked to allow your device to perform at its best.
Use your device on a hard flat surface, such as a table or desk, for optimal temperature control. If you're using your device on a soft surface, such as a sofa, pillow, bed or your lap, its fans may run more.
Check for unexpected heavy fan use
If the fans in your device are running fast even when it isn't experiencing heavy usage and is properly ventilated, follow the steps for your device:
- On an Intel-based Mac: reset the System Management Controller (SMC)
- On a Mac computer with Apple silicon: close and open the lid on your notebook, or restart your computer.
- On an Apple TV 4K, AirPort Extreme or AirPort Time Capsule: unplug the device, then plug it back in.
- On a Mac Pro: check the enclosure to make sure your Mac Pro is locked and fully seated, or that the top cover or access door is closed and locked on rack-mounted models.