Activity Monitor in action

Activity Monitor is a utility from Apple Inc. that comes on all Macintosh computers running Mac OS X. It was previously called ProcessViewer.

Activity Monitor measures how resources are being used by different processes (or applications) on a Macintosh. This can them be used to monitor the Mac's processor and disk activity, as well as the memory usage and network activity.

Using this utility can be useful to monitor applications which draw heavily on the Mac's processor, such as graphics, DV editing, and 3D rendering programmes.

If needed, the Dock icon can be switched to keep an eye on the specific usage.

All charts are shown as dotted bar graphs.


Using Activity Monitor, the user can inspect individual applications and their usage of the computer's resources. The process list can also be saved and be exported. There is also an option to filter what can be seen. Finally, there is an option to quit or force quit an inactive application.

CPU, System Memory, Disk Activity, Disk Usage and Network usage can all be seen by means of toggable switches at the lower part of the window.

Relation with the Classic Mac OS

Memory usage, previous part of the About This Macintosh... option on Macs running the Classic Mac OS, can be seen using this utility.


Mac OS X Boot Drive > Applications > Utilities > Activity Monitor