Click Finder > Applications > Utilities > Activity Monitor. The Activity Monitor allows you to view the system CPU usage in real time.
Click the CPU tab to view the CPU stats.
Any process can be selected for deeper inspection. To inspect a process, double-click it from the Activity Monitor. In the window you'll find information about an application's memory usage, various statistics, and a list of files that the process is making use of.
Viewing the CPU Stats
CPU Parameter
Description
Value
Suggested Average Threshold
% CPU
Shows the CPU percentage that each process is using.
1.50%
10-15%; threshold can increase if Iguana is the only main application running on the machine (not including background processes). For the most part this number should be below 20%, with only the occasional spike.