# How to check CPU and memory use on a Mac > Open Activity Monitor and click CPU or Memory to see what is using your processor and RAM, and how to read memory pressure. Canonical: https://www.notchstar.com/tips/check-cpu-and-memory-use-on-mac/ Last updated: 2026-11-04 Published 2026-11-04. Open Activity Monitor, click the CPU tab to see processor use, and click the Memory tab to see RAM use. The numbers at the bottom of each tab give the summary, and the list above shows which apps and processes are responsible. ## CPU 1. Open **Activity Monitor**. It is in the Utilities folder inside Applications, and Spotlight finds it by name. 2. Click the **CPU** tab. 3. Read the percentages at the bottom: **System** is CPU use by macOS processes, **User** is use by the apps you opened and their processes, and **Idle** is unused capacity. 4. Choose **Window > CPU Usage** for current activity or **Window > CPU History** for recent activity. To put a CPU graph in the Dock, choose **View > Dock Icon** and then pick a **Show CPU** option. ## Memory 1. Click the **Memory** tab. 2. Read the bottom of the window: **Physical Memory** is the installed RAM, **Memory Used** is the RAM in use (with **App Memory**, **Wired Memory** and **Compressed** next to it), **Cached Files** are files kept in unused memory to speed up reopening apps, and **Swap Used** is space on the startup disk used to swap files to and from RAM. 3. Look at the **Memory Pressure** graph. Apple says green means RAM is used efficiently, yellow means your Mac might eventually need more, and red means it needs more RAM. ## Find the app causing it Click a column heading to sort the list, and click again to reverse it. Type a name in the search field to find a process. Select a process and double click it, or click the Info button, for details. Use the **View** menu to switch between choices such as **All Processes** and **My Processes**. If a process misbehaves, see [quitting an app in Activity Monitor](https://www.notchstar.com/tips/quit-an-app-in-activity-monitor/). ## High use is not always bad A busy CPU while you export a video is normal. Memory in use is also normal, because macOS uses spare RAM to speed things up. The signs to watch are a red memory pressure graph, or a process that stays high when you are not using it. ## For battery use If the question is power, see [which app uses the most energy](https://www.notchstar.com/tips/see-which-app-uses-the-most-energy-on-mac/). ## A glance in the notch NotchStar's [System tool](https://www.notchstar.com/features/system-stats/) shows CPU, memory, disk and battery rings and a network readout, sampled once a second while the tab is open. It shows totals only, with no per app breakdown, so use Activity Monitor when you need to find which process is responsible. ## Quick answers. ### What do the colors of the memory pressure graph mean? Apple says green means your Mac is using all of its RAM efficiently, yellow means it might eventually need more RAM, and red means it needs more RAM. ## Keep reading. - [CPU, memory, disk, battery and network](https://www.notchstar.com/features/system-stats/): Live CPU, memory, disk, battery and network speed gauges in your Mac notch. Sampling only runs while the tab is open, so it stays light. - [How to see which app uses the most energy on a Mac](https://www.notchstar.com/tips/see-which-app-uses-the-most-energy-on-mac/): Open Activity Monitor, click Energy, and sort by Energy Impact or 12 hr Power to find the apps draining your battery, and spot apps keeping the Mac awake. - [How to quit an app that is using too much CPU](https://www.notchstar.com/tips/quit-an-app-in-activity-monitor/): Select the app in Activity Monitor, click the Stop button and choose Quit or Force Quit. What each does, and why not to force quit casually. - [How to check your Mac battery health](https://www.notchstar.com/tips/check-mac-battery-health/): Open System Settings, Battery, and click the Info button beside Battery Health to see condition and maximum capacity. Also charge and longevity options. - [Disk space, duplicates, apps and cleanup](https://www.notchstar.com/features/disk/): See free space, find big folders, duplicates and app leftovers, compress media and clean caches from your Mac notch. Everything goes to the Trash. ## More in System and battery. - [How to check your Mac battery health](https://www.notchstar.com/tips/check-mac-battery-health/): Open System Settings, Battery, and click the Info button beside Battery Health to see condition and maximum capacity. Also charge and longevity options. - [How to see which app uses the most energy on a Mac](https://www.notchstar.com/tips/see-which-app-uses-the-most-energy-on-mac/): Open Activity Monitor, click Energy, and sort by Energy Impact or 12 hr Power to find the apps draining your battery, and spot apps keeping the Mac awake. - [How to turn on Low Power Mode on a Mac](https://www.notchstar.com/tips/turn-on-low-power-mode-on-mac/): Choose Low Power under Energy Mode in System Settings, Battery, separately for battery and power adapter. Which Macs Apple says support it. - [How to quit an app that is using too much CPU](https://www.notchstar.com/tips/quit-an-app-in-activity-monitor/): Select the app in Activity Monitor, click the Stop button and choose Quit or Force Quit. What each does, and why not to force quit casually.