There are various ways on a Mac that you can keep track of your system’s CPU, disk, memory, and network usage. One of the popular options is the iStat Menus which displays some pretty graphs and stats in your Mac menu bar. It sucks that it isn’t free, but there is an alternative that I bet a lot of you will enjoy almost as much called MenuMeters.
With MenuMeters you can heavily customize how you want the data to appear in the Mac menu bar for your CPU, storage, memory usage, and network throughput. If you don’t have a lot of space available in your menu bar you can configure it to use a minimal amount of space, and yet you’ll still be able to uncover a lot of the information by clicking on the respective items in the menu bar. As you can see in the screenshot above you can get more details about the CPUs when you click on the menu bar item that shows the usage of each core.
Information like this can be extremely useful when troubleshooting issues, and you can quickly toggle them on or off using the MenuMeters preference pane that appears in your Mac’s System Preferences. So you can always get it installed so that it is ready and waiting for when you need it.
MenuMeters Homepage (Mac only; Freeware)