But for the occasional test, it’s nice to have control-just turn things back to automatic when you’re done. I really do not recommend disabling the automatic fan control: leaving your fans on constantly will wear them out and waste energy, and leaving them off will overheat your Mac over time. Turn the fan up and see if you can hear anything. To find out if your fans are working at all, you can click the “Custom” speed button. The same goes if you see a low CPU temperature-say, around 45-and the fans are running at full speed. If you see high CPU temperatures-say, over 80 or 90 degrees-and that the fans aren’t running, you might have an issue. The minimum, current, and maximum speed are shown in that order. For the most part, however, we’re interested in your fan’s current speed.
