Maintaining Mac Pro - Teach Yourself Visually Complete Mac Pro - page 768

Monitor the System value to track the percentage of the CPU that OS X is using.
Monitor the User value to track what percentage of the CPU your running programs
are using.
TIPS
What do I do if a program is stuck at 100 percent CPU usage for a long
time?
Although rare, a program can stay at 100 percent usage for a few minutes while it com-
pletes a CPU-intensive task. If after 5 minutes or so the program is still showing 100 per-
cent usage, you should shut it down. Click the program and then click Force a process to
quit ( ). When Activity Monitor asks you to confirm, click Force Quit .
Is there a way to monitor CPU usage without having to switch to the
Activity Monitor window?
Yes, you can convert the Activity Monitor Dock icon into a CPU usage graph. Click View ,
click Dock Icon , and then click Show CPU Usage .