How to use the Activity Monitor to troubleshoot your Mac : Not many regular users know about the OS X Activity Monitor, and don’t know how it works and what it can do. Here’s how to use the Activity Monitor to manage your Mac memory, fix slow applications, and solve other problems.
Open the Activity Monitor application by going to Applications > Utilities > Activity Monitor, or simply type “activity monitor” in Spotlight. The main Activity Monitor screen is divided into two parts:
1. The Processes Table
The main pane displays a list of open applications and system processes. Note that even if you just stare at the desktop and do nothing, how many items are displayed in the Processes list. Some applications are easy to find, while others are background system-level operations that you don’t usually see. All processes are listed along with more details in each column.
You can view other columns by the process of the View > Columns menu. Expand the Columns option and select the options you want to view, which will appear in the Activity Monitor. You can also sort the list of processes. In the top right corner, there is a Search Filter box that lets you search for a specific process.
2. System Monitor Tabs
Five category tabs at the top of the Activity Monitor – “CPU”, “Memory”, “Energy”, “Disk” and “Network” – Focus on the list of processes on a given resource. For example, if you want to see which processes are using RAM, you can click the Memory tab. If you want to see content that occupies so much network bandwidth, click Network.
Actual time statistics are updated every five seconds, but you can shorten or extend the time by going to View > Update Frequency and selecting a frequency level. These monitoring features are very useful for troubleshooting.
The View menu also allows you to select which processes you see: all processes, system processes, active processes, applications used in the past 8 hours, and more. You can read more about these options in Apple’s support documentation.