HOW TO Use Activity Monitor >

One common resource hog is the kernel_task process, which sometimes maxes out your CPU for no apparent reason. A reboot is a quick fix but if the problem recurs you’ll need to reset your Mac’s System Management Controller.

1 Open the app

Activity Monitor lets you see exactly what’s running on your Mac and what resources everything is using. To launch it, press ç+[spacebar], type ‘activity’ and then press ®. Or you can launch it from Applications > Utilities.

4 Who’s the hog?

Look at CPU usage to see what’s driving your Mac the hardest. Here we can see that Logic Pro is using 27.3% of our CPU while it exports a project. If an apparently idle app is using lots of power, quit and restart it: if it’s Safari, close tabs.

2 See what’s running

If you go to View > Windowed Processes you can simplify what’s on screen: instead of seeing every individual process, which can be a bit intimidating, this option shows only the apps that are currently running.

5 See everything

If you’re feeling more confident, viewing All Processes enables you to see the individual processes each app is using – and in the case of Safari, each individual tab. That’s useful for spotting overly demanding websites.

3 Sort it out

Click on a column header to sort, so for example if you want to list apps alphabetically click ‘Process Name’. You can view different resources by clicking the appropriate button: CPU, Memory, Energy, Disk and Network usage.

6 Check the kernel