Does it seem like your Mac is running slowly? It’s always possible that you need more RAM, a speedy SSD to replace a slow hard drive, or even a new Mac. But you might just have a rogue app that’s hogging your Mac’s CPU.
Activity Monitor shows the processes that are running on your Mac, so you can manage them and see how they affect your Mac’s activity and performance. Activity Monitor is a kind of task manager that allows you see how apps and other processes are affecting your your CPU, memory, energy, disk, and network usage.
Activity Monitor is bundled with every Mac. Open your Applications folder and scroll down until you see the Utilities folder. Open that to find and double-click Activity Monitor.
The processes shown in Activity Monitor can be user apps, system apps used by macOS, or invisible background processes. Use the five category tabs at the top of the Activity Monitor window to see how processes are affecting your Mac in each category.
* CPU
* Memory
* Energy
* Disk
* Network
Activity Monitor can seem daunting because it lists every “process” running on your Mac. In many cases, a process is the same as what you think of as an app, so you’ll see processes for apps like Mail and Safari. However, some apps use multiple processes, and macOS itself relies on a ton of processes too. You can limit the processes you are looking at with the View menu. There you have the choice of limiting your view to:
* All Processes
* All Processes Hierarchically: Processes that belong to other processes, so you can see the parent/child relationship between them.
* My Processes: Processes owned by your macOS user account.
* System Processes: Processes owned by macOS.
* Other User Processes: Processes that aren’t owned by the root user or current user.
* Active Processes: Running processes that aren’t sleeping.
* Inactive Processes: Running processes that are sleeping.
* Windowed Processes: Processes that can create a window. These are usually apps.
* Selected Processes: Processes that you selected in the Activity Monitor window.
* Applications in the last 8 hours: Apps that were running processes in the last 8 hours.
Those views show the impact each process has on those aspects of the Mac. For now, we’ll focus on the CPU view that’s the default, but if you were trying to figure out why your MacBook Pro’s battery was draining so quickly, you’d look in the Energy view.
At the bottom of the CPU view is a graph of CPU load, and numbers that correspond to how much of that load comes from the system and how much from the user (apps you’ve launched). As long as the sum of those numbers stays under 100% most of the time, you’re probably fine. But if you’re near or at 100%, you’ll want to hunt for rogue processes.
To identify them, click the % CPU column header to sort the process list by CPU power. If necessary, click again to change the direction of the sort so the arrow next to % CPU is pointing down, so those processes using the most CPU power are at the top. Be aware that the percentages in this column are by core (unlike the graph and numbers at the bottom), so a runaway app on a 4-core iMac could claim to be using as much as 400% in the % CPU column.
Now watch the list for a while. If one process is sucking CPU power, you’ll see it at the top of the list. If it matches an app you’ve launched, quit that app to give other apps a chance at the CPU. That often solves your problem quickly. In the most extreme case, the process name will be in red, which means it’s not responding, at which point you can force quit it by selecting it and then clicking the X button at the left of Activity Monitor’s toolbar.
You can use Activity Monitor to quit a process, even if it’s in a loop or not responding. You can also send a signal to a process to terminate it. If you attempt to quit a process you don’t own, you may be required to authenticate as an administrator.
# In the process list, select the app or process you want to quit. An unresponsive process is marked with (Not Responding).
# Click the “Force quit” button in the upper-left corner of the Activity Monitor window.
# Choose one of the following options:
* Quit: This is the same as choosing File > Quit within an app. The process quits when it’s safe to do so. If quitting the process could cause data loss or interfere with another app, the process doesn’t quit.
* Force Quit: The process quits immediately. If the process has files open, you may lose data. If the process is used by other apps or processes, those apps or processes could experience problems.
To see if a process is used by another process, choose View > All Processes, Hierarchically.
Equally likely, though, is that the top process will be one you don’t recognize immediately, like backupd (Time Machine), mds or mdworker (Spotlight), photolibraryd or photoanalysisd (Photos), or kernel_task or WindowServer (core macOS functionality). You can’t (or at least shouldn’t) quit those processes manually, but at least you’ll know that things are slow due to a Time Machine backup running, Spotlight indexing new files, or Photos analyzing the images in your library. If one of these processes has gone nuts, the best solution is to restart your Mac.
You might need more memory. To see how your memory is being utilized you would go to the Memory tab of Activity monitor where you can see the amount of system memory being used on your Mac. The Memory pane displays how much memory your Mac is using, how often it is swapping memory between RAM and your startup disk, and the amount of memory provided for an app and how much of it is compressed memory.
* Memory Pressure: Graphically represents how efficiently your memory is serving your processing needs.
Memory pressure is determined by the amount of free memory, swap rate, wired memory, and file cached memory.
* Physical Memory: The amount of RAM installed.
* Memory Used: The amount of RAM being used and the amount that’s immediately available.
* Cached Files: The size of files cached into unused memory to improve performance.
* Swap Used: The amount of space being used on your startup disk to swap unused files to and from RAM.
* 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 compressed memory in RAM.
When your computer approaches its maximum memory capacity, inactive apps in memory are compressed, making more memory available to active apps. The Compressed Mem column indicates the amount of memory being compressed for an app.
The key to understanding whether you need RAM is the Memory Pressure graph. The Memory Pressure graph lets you know if your computer is using memory efficiently.
* Green memory pressure: Your computer is using all of its RAM efficiently.
* Yellow memory pressure: Your computer might eventually need more RAM.
* Red memory pressure: Your computer needs more RAM.
If memory pressure is yellow, red, or has spikes, check to see if an app is using up memory and causing the memory pressure to increase. If you no longer need to have the app running, you should quit the app.
Your computer’s memory pressure is accurately measured by examining the amount of free memory available, the swap rate, and the amount of wired and file cached memory to determine if your computer is using RAM efficiently.
Activity Monitor is a powerful tool and we will talk about Energy, Disk and Network panes in a future issue. But if you are finding yourself staring at the beach ball a lot your first step should be to check out CPU and Memory panes in the Activity Monitor.
