I was a little bummed to find my CPU busy all morning yesterday. And though I still don’t understand exactly what was causing it, it seems no longer to be a problem. A lot of people don’t know how to see what their Mac is doing, to see what it’s busy with. Here are some hints:
Start with Activity Monitor in Applications > Utilities. From there you can see and sort applications and processes that are running on your computer. Be sure to show “All Processes,” otherwise you’ll only see the applications you’re now using. Click the “%CPU” column to sort the list by which app is hogging your processor the most. Down at the bottom of the window, you can see activity graphs for CPU, memory, disk activity and usage, and network.
For a different view, and more detail on some information, go to the Terminal application and start top with this command:
top -u
Understanding the output is another issue, but you can’t break anything from there so don’t worry. Use “q” to quit.
The X Lab has a few more detailed articles on viewing and understanding Mac OS X performance, incuding: performance tuning tips, spinning beach balls, and how lack of RAM and disk affect performance.
There’s another story that describes odd performance problems at Betalogue.