If you’re only interested in user processes, then turn off the clutter of All Processes, for instance.

You can also customise which processes get listed in this window, using the View menu. One snag of doing that is that the order keeps changing, of course. Click in its header once to sort the list of processes into order with the highest %CPU at the top.

In most cases, the defaults are an excellent start, and the %CPU column the most significant to watch. You can customise which fields are shown by Control-clicking in the column headers, which pops up the menu of items you can include, and you can drag and drop the columns into the order that you want. The main window lists active processes and key values which normally include %CPU, CPU Time, Threads and more. Understanding what you see is the next challenge. All you have to do is open Activity Monitor and select its CPU view. Unlike the log, access provided by Activity Monitor is excellent only developers with Xcode’s performance tools have any better, and then only for their own code. This article looks at using the latter to learn more about what your Mac’s processor cores are up to, and what might be causing it problems. For observing Macs and macOS there are two major tools: the Unified Log, which unfortunately is still poorly supported by the bundled browser, and Activity Monitor. If you want to know about anything, start by observation.

Cpu activity monitor