What’s slowing me down?
When something on your Mac unexpectedly grinds to a halt, here’s how to get the lowdown on what’s really happening behind the scenes When your Mac‘s slowed by something using lots of resources, use this tool to identify it
Think of Activity Monitor as a window on the internal workings of your Mac, observing its processor, memory, energy, storage and network access, and which apps or services are using the most of each. Almost always, when an app is slowing down your computer by consuming more than its fair share of resources, this tool will help you to identify that app so you can take remedial steps.
Although it looks threatening to the uninitiated, it doesn’t take long to get acquainted with Activity Monitor’s way of working. Before we dive in to it, though, a word of warning: save your work before you do anything, as quitting processes (which is what Activity Monitor calls both applications and background services) can cause you to lose data in open apps.
Starting at the bottom of the window, the graph at the centre is a timeline showing how resource usage has changed over time. The most recent measurement is always on the far right. Why the two colours? Blue represents the resources used by processes (apps and their related services) that have been initiated by your user account, whereas red indicates what OS X has initiated itself.
Running processes are listed in the table above; the User column shows who is responsible for each – you or OS X. You can cluster them by clicking the column’s header. Clicking the Process Name header sorts them alphabetically, while clicking any other one sorts things in ascending or descending numerical order to help quickly find the biggest resource hogs.
Unresponsive processes will be red; black ones are running normally, and you can quit one of either by selecting it and clicking the first button on the toolbar – the circle with a cross in it. Avoid doing this to processes instigated by OS X, as they’re often vital to the system running smoothly, and manually shutting them down can cause the Mac to crash.
Two sections – Network and Energy – don’t directly relate to the physical specs of your Mac. Network is where you should look if your internet connection’s running slow, as you may spot a rogue process that’s sending or receiving an inordinate amount of unexpected data. Click Energy if your Mac is running hot or a MacBook’s battery isn’t lasting as long as you expect.