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    Mac Activity Monitor: Find What's Using Your Memory and CPU and Fix Slowdowns

    Activity Monitor shows you what is running on your Mac and how much power each app uses. Learn how to spot and stop programs that are slowing your computer down.

    5 min read 5 stepsApril 20, 2026Verified April 2026
    1

    Open Activity Monitor

    ~30s
    Click the magnifying glass icon (Spotlight) in the top-right corner of your screen, or press Command + Space. Type "Activity Monitor" and press Enter. Alternatively, open Finder, click "Go" in the menu bar at the top, choose "Utilities," and double-click Activity Monitor from the list. The app opens showing a live table of every process running on your Mac.

    Quick Tip

    Quick Tip: Activity Monitor updates itself every 5 seconds by default. You can change this speed in the View menu by choosing "Update Frequency" — set it to "Very often" if you want more responsive readings.

    2

    Check the CPU tab

    ~33s
    Click the "CPU" tab near the top of the Activity Monitor window. The list shows every process and how much CPU each is using, expressed as a percentage. Click the "% CPU" column header to sort from highest to lowest. A well-behaved Mac at rest should show most processes using less than 5% CPU. If a single process is constantly using 50% or more, something is wrong.

    Warning

    Some intensive tasks legitimately use high CPU temporarily — a video conversion, a software update downloading, or Time Machine backing up files. High CPU is only a concern if it persists when your computer should be idle.

    3

    Check the Memory tab

    ~36s
    Click the "Memory" tab. Sort by "Memory" to see which apps use the most. At the bottom of the window, look for "Memory Pressure" — a graph that shows whether your Mac has enough RAM. A green graph means RAM is fine. A yellow or red graph means your Mac is running out of working memory and performance may suffer. The "Used" number at the bottom shows how much RAM is currently in use.

    Quick Tip

    Quick Tip: If your Mac has 8 GB of RAM and you regularly see Memory Pressure in yellow or red, adding more RAM (on models that allow it) or reducing the number of apps you run simultaneously will help.

    4

    Force quit a misbehaving process

    ~36s
    If you see a process using extremely high CPU or memory and you do not recognize it, search for its name online to learn what it is before taking action. If it is a frozen or misbehaving app, click on it in the Activity Monitor list and then click the X button in the top-left corner of the Activity Monitor window. A dialog asks whether you want to "Quit" (graceful close) or "Force Quit" (immediate termination). Choose Force Quit only if the regular Quit does not work.

    Warning

    Force quitting an app closes it immediately without saving your work. Use Quit first. Only use Force Quit if the app is unresponsive and Quit has no effect.

    5

    Check the Energy tab for battery drain

    ~36s
    On a MacBook, click the "Energy" tab to see which apps are using the most power. Apps using high energy drain your battery faster. Sort by "Energy Impact" to see the biggest consumers. If an app you barely use shows high energy usage, consider closing it when you do not need it. The "12 hr Power" column shows average energy use over the past 12 hours, which is more meaningful than a momentary reading.

    Quick Tip

    Quick Tip: Web browsers — especially with many tabs open — are often the largest energy consumers on a MacBook. Closing tabs or browser windows you are not actively using can meaningfully extend battery life.

    You Did It!

    You've completed: Mac Activity Monitor: Find What's Using Your Memory and CPU and Fix Slowdowns

    Need more help? Get Expert Help from a TekSure Tech

    Activity Monitor is a built-in Mac utility that shows you in real time what is happening inside your computer. It lists every process and app running on your Mac along with how much of your computer's resources each one is using — specifically CPU (processing power), memory (RAM), energy, disk activity, and network data.

    CPU stands for Central Processing Unit — the main "brain" of your computer that runs programs and calculations. Memory (RAM) is the working space your computer uses to hold programs and data that are currently active. When either of these is nearly full, your Mac slows down. Activity Monitor helps you identify which programs are using the most resources so you can close the ones causing problems.

    Think of your Mac's memory like desk space. Each app you have open takes up some of that space. If you have too many apps open — or one app is taking up an enormous portion of the desk — other tasks slow down because there is not enough room to work efficiently. Activity Monitor shows you which app is the "messy occupant" taking far more than its fair share.

    Common culprits for Mac slowdowns include web browsers with many tabs open (each tab uses memory), applications that have been running for days without being restarted, software that has developed a "memory leak" (a bug that causes it to gradually consume more and more memory), and background processes that might be running without you realizing it.

    Activity Monitor is available on all Macs and is always installed as part of macOS. It is located in the Applications > Utilities folder. Checking it occasionally is a good habit, especially when your Mac feels sluggish.

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    Official Resources

    Apple SupportHow-To Geek — MacApple Support YouTube

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    Mac Activity Monitor: Find What's Using Your Memory and CPU and Fix Slowdowns — Step-by-Step Guide | TekSure