OS X Mavericks: About Activity Monitor

Activity Monitor can be used to view how processes (apps and background processes) are using resources on your Mac, such as the processor, memory, disk, network and overall energy usage.

Activity Monitor

Activity Monitor provides information about the processes and resources in use on your Mac. Each tab of the Activity Monitor window provides information about a different subject.

CPU, Disk, and Network

Select CPU, Disk, or Network near the top of the window to see the CPU, Disk, or Network usage for running processes. These categories contain similar information to what was shown in previous versions of Activity Monitor, except now you can view the Disk and Network usage for individual processes. If your Internet connection has a limit on the amount of data you can download, and you want to identify which processes are downloading the most data, click Network then click on the Rcvd Bytes column heading to sort based on this column.

Controlling which processes are shown

You can control which processes are shown in Activity Monitor by choosing any of the following from the View menu:

  • All Processes
  • All Processes Hierarchically
  • My Processes, System Processes
  • Other User Processes, Active Processes
  • Inactive Processes, Windowed Processes
  • Selected Processes
  • Applications in the last 8 hours

Each category in Activity Monitor (CPU, Memory, Energy, Disk, and Network) can be configured to display a different set of processes. The name of the currently selected view is shown in the title that appears at the top of the Activity Monitor window.


Click Memory near the top of the Activity Monitor window to view system memory usage and to see how much memory is being used by active processes. This Memory category replaces the System Memory category in previous versions of Activity Monitor. 

The combination of Free, Wired, Active, Inactive & Used memory statistics in previous versions of Activity Monitor have been replaced in Mavericks with an easy to read "Memory Pressure" graph.

Memory pressure is indicated by color:

  • Green – RAM memory resources are available.
  • Amber – RAM memory resources are being tasked.
  • Red – RAM memory resources are depleted and OS X is using the drive for memory.

Tip: If the Red state occurs, quitting apps can free up RAM. You may also be able to install more RAM to prevent memory depletion.

The graph moves from right to left, with the most recent memory sample on the right side of the graph. Previous samples are moved to the left as the graph updates. In the above example, the Mac's RAM memory was previously heavily tasked (Amber) to the point of depletion (Red). However RAM memory is now available (Green). 

Additional details covered by the Memory pane include:

  • Physical Memory: The amount of RAM installed.
  • Memory Used: The amount of RAM being used and not immediately available for other apps.
  • Virtual Memory: The amount of memory mapping that apps have asked for. This is not an actual consumption of RAM resources and it size is determined by the author of the app.
  • Swap Used: The space on your drive being used to swap unused files to and from RAM. It is normal to see some activity and it is not an indication that you have depleted RAM resources. Seeing memory pressure in the Red state will indicate that RAM resources are depleted.
  • App Memory: The amount of space being used by apps.
  • Wired Memory: Memory that can’t be cached to disk, so it must stay in RAM. This memory can’t be borrowed by other apps.
  • Compressed: The amount of memory in RAM that is compressed, making more RAM resources available for other apps.
  • File Cache: The space in RAM marked as available for apps to use that contains recently used files.

As an example of how File Cache works, if you've been using Mail and then close it, the RAM that Mail was using is marked as File Cache. This RAM is now available for use by another app. If you open Mail again before its File Cache is used (overwritten) by a different app, Mail opens more quickly because its File Cache memory is converted back to App memory instead of loading all of its contents from your drive.


Click Energy near the top of the Activity Monitor window to see how much energy is being consumed by open apps and background processes. The amount of energy being used affects how much energy your Mac is using, and how long you can operate your portable Mac with no power adapter connected.

activity monitor energy

Energy Impact

The Energy Impact shown at the bottom of the window represents the total amount of energy used by all processes over a period of time. To determine how much energy is being used by individual processes, look at the number that appears in the Energy Impact column next to the name of each process. The lower the Energy Impact number, the less power the process is currently using. If you see a triangle to the left of an app's name, it means that the app consists of multiple processes. Click on the triangle to view details on the processes that are part of that app.

Avg Energy

The Avg Energy Impact column shows the average Energy Impact for each process over the past 8 hours or since the last time the Mac started up (whichever is shorter). Any processes where the name appears in gray are not currently open, but you can still view the average Energy Impact to date for those processes. If you notice that the battery life on your portable Mac is shorter than usual, you can click on the Avg Energy Impact column heading to sort based on this column. Processes with the highest average Energy Impact have consumed the most power recently. You can quit these processes if you do not need them, or contact the developer of the app for support if you notice that its Energy Impact remains high even when the app does not appear to be doing anything.

App Nap

OS X Mavericks includes a technology called App Nap. App Nap allows supported apps to consume very little energy when they are open but not being used. For example, App Nap might be used if an app is open on a desktop that you are not currently viewing, or if an app is hidden under other windows. You can determine if an app is currently using App Nap by looking at the App Nap column next to the name of the app in the Activity Monitor window.

Graphics switching

Macs that support automatic graphics switching save power by using integrated graphics and switch to a higher performance graphics chip only when an app needs it. Activity Monitor shows "Graphics Card: Integrated" when using integrated graphics, or "Graphics Card: High Perf." when using high performance graphics. To identify which apps are using high performance graphics, look for processes which show "Yes" in the Requires High Perf GPU column.

Battery graph

If you are using a portable Mac, there is a Battery graph at the bottom of the window that shows the battery's charge level over the past 12 hours. The sections of the graph with a green background indicate times when the Mac was receiving power from a power adapter. 

Learn More

Select Activity Monitor Help from the Help menu to learn more about using Activity Monitor. You can also see additional details about column headings, or the statistics shown at the bottom of the Activity Monitor window by moving your pointer over the item you are interested in. Tool tips appear with more information when you leave your pointer over one of these items.

Additional information about OS X memory management is available from the Apple Developer website

Important: Information about products not manufactured by Apple is provided for information purposes only and does not constitute Apple’s recommendation or endorsement. Please contact the vendor for additional information.
Last Modified: Aug 22, 2014
  • Last Modified: Aug 22, 2014
  • Article: HT5890
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