Best for: checking whether a disk is about to fail. The first handy thing you. Fast.com is a super-simple WiFi speed test app for Mac and other computers and devices with a modern web browser. Unlike most other similar apps, Fast.com only measures your download speed, and it does so as soon as you open it.
Close unresponsive apps and processes
When your system is acting sluggish or simply not responding, an app or process may be the source of the problem. You can use Activity Monitor to locate the troublesome app or process and force it to quit.
See how much energy your Mac is using
You can find out how much energy your Mac is using, and see which apps or processes are using the most energy.
See real-time CPU, network, or disk status in the Dock
It’s easy to keep an eye on your system status without even looking at the Activity Monitor window—you can monitor your CPU, network, or disk usage as a live graph right in the Dock.
Mac Performance Test Online
To explore the Activity Monitor User Guide, click Table of Contents at the top of the page, or enter a word or phrase in the search field.