Glossary
Activity Monitor, explained.
Every process name and term you're likely to meet in Activity Monitor: what it is, whether to worry, and what to do about it.
Processes
kernel_task
The core of macOS. When it uses a lot of CPU, it is usually keeping your Mac cool by holding other work back.
WindowServer
The macOS process that draws everything you see on screen: windows, the Dock, the menu bar and animations.
mds_stores, mds and mdworker
Spotlight's indexing processes. They read your files so Spotlight search can find them.
photoanalysisd
Analyzes your Photos library to recognize people, places and scenes for search and Memories.
mediaanalysisd
Analyzes images and video for features like Live Text and Visual Look Up.
backupd
The Time Machine backup process.
cloudd
Syncs app data with iCloud (CloudKit).
fileproviderd
Manages files from iCloud Drive and other cloud storage apps in Finder.
launchd
The first process macOS starts. It launches and manages almost everything else.
logd
Collects the system's unified log.
syspolicyd
Checks that apps are safe to open (Gatekeeper).
nsurlsessiond
Handles background downloads and uploads for macOS and apps.
coreaudiod
The macOS audio engine.
sharingd
Powers AirDrop, Handoff and other sharing features.
rapportd
Lets your Apple devices talk to each other for Continuity features.
Memory
Memory pressure
How hard macOS is working to give apps the memory they need: green, yellow or red.
Swap used
Data macOS has moved from memory to the disk because memory was full.
Compressed memory
Memory macOS has squeezed to make room before resorting to swap.
Cached files
Recently used data macOS keeps in spare memory so it can open it faster next time.
App memory and wired memory
App memory is used by your apps; wired memory is reserved for macOS and can't be moved.
CPU & energy
% CPU
How much processor time a process uses. Each core counts as 100%, so it can go above 100%.
Load average
The average number of tasks waiting for or using the processor over the last 1, 5 and 15 minutes.
Energy Impact
A relative score of how much power an app is using right now.
App Nap
macOS slows apps that are hidden and idle to save power.
Preventing Sleep
Shows which apps are keeping your Mac awake.
Performance and efficiency cores
Apple silicon Macs have fast performance cores and power-saving efficiency cores.
PID (process ID)
The unique number macOS gives every running process.