Memory pressure

Green: memory resources are available, and the Mac is using its RAM efficiently.

Yellow: memory is still available, but macOS is working to provide it, for example by compressing memory. Apple's guidance is that the Mac might eventually need more RAM.

Red: memory is depleted and macOS is using the startup disk as memory (swap). Apple's guidance is that the Mac needs more RAM for what you are doing.

Brief periods of yellow are normal, for example when you open a large project or many tabs at once. It becomes a concern if it stays yellow for most of the time you use the Mac, or if it often reaches red.

When it is yellow or red, sort the Memory tab by the Memory column to see which apps are using the most, and quit ones you do not need.

Run fewer memory heavy apps at once, close browser tabs, and quit apps that grow over time. If pressure stays high with your normal workload, the Mac needs more RAM for that work. On many Macs memory cannot be upgraded after purchase; you can check in System Information, under Hardware, Memory.

Memory pressure is only shown in one place in Activity Monitor, so it helps to know exactly where to look.

1. Open Activity Monitor. It is in the Utilities folder inside Applications, or you can search for it with Spotlight.
2. Click the Memory tab at the top of the window.
3. Look at the Memory Pressure graph at the bottom of the window. The color of the newest part of the graph is the current state.
4. Leave the window open while you work for a while. Activity Monitor updates every 5 seconds by default, and you can make it faster with View > Update Frequency.

Apple's advice is that if memory pressure is yellow, red, or has spikes, you should check whether an app is using up memory, and quit it if you no longer need it. These steps do that.

1. In the Memory tab, choose View > All Processes so background processes are included, not only your own apps.
2. Click the Memory column heading so the largest users are at the top. Click it again if the order is reversed.
3. Note the top few rows. Apps with helper processes appear as several rows, so add those rows together.
4. Select an app you do not need right now, click the Stop button at the top of the window, then click Quit. Use Force Quit only if the app does not respond, because unsaved work can be lost.
5. Watch the Memory Pressure graph. If it drops back to green after you quit the app, you have found the cause.

Memory pressure goes up when running apps ask for more memory than the Mac can give them without compressing or swapping. The usual reasons are:

• Many browser tabs, especially web apps that stay open for days.
• Virtual machines and containers, which reserve a large block of memory while they run.
• Large photo, video, audio or design projects.
• Developer tools such as compilers, indexers and local servers running at the same time.
• An app with a memory leak, whose Memory figure keeps climbing while you are not doing more with it.
• Many apps left open for a long time, each holding memory it no longer needs.

Normal: the graph is green most of the time, with short yellow periods when you open something large. The Mac stays responsive.

Worth watching: the graph sits in yellow for long stretches during your usual work, and Swap Used keeps growing during the day.

A problem: the graph reaches red often, apps pause when you switch between them, and the spinning wait cursor appears more than usual. At that point, either run fewer heavy apps at once or plan for a Mac with more memory.