High CPU usage can lead to several problems on Macs. If left untouched, you may encounter application crashes, a frequent jittery interface with a spinning beachball, overheating, shorter battery life, and worse – kernel panics. This tutorial shows you the steps to identify the processes using excessive CPU and how to fix them.
Tip: If you’re working with an older Mac, learn how you can get some new parts and upgrade it to being like new.
Identifying the Processes Consuming Excessive CPU
At the most basic, a Mac user should be aware of the different types of processes and the ins and outs of using Activity Monitor. To display the processes consuming the highest %CPU:
- Launch Activity Monitor and click the CPU tab.
- Click the column header once to sort them in descending order.
- Choose “Window → CPU History.”
- Open a new “CPU History” window that shows the user and system load in each core with time.
- You must also make note whether a given process is an app or belongs to the system. Application-based processes have an icon next to their name and are tied to your user account, in this case, “rahulsaigal.”
- Those processes that don’t have an icon next to their name and are owned by “root” belong to the system.
The CPU tab highlights some important metrics.
- %CPU is the percentage of total processor capacity the process consumes, e.g., the processor capability.
- CPU Time is the length of time a process has been active since the last startup.
- Idle Wake Ups is the number of times a process woke up from the sleep state.
For Apple Silicon Macs, you’ll understand how the Icestorm (or Efficient) and Firestorm (or Performance) cores behave. Most system-based processes (Spotlight indexing, Time Machine backups) use E cores. Apps and related user processes run on either E or P cores with a preference towards P cores.
Helpful Hint: wondering if an app has been optimized for your Apple Silicon Mac? We show you how to check.
Managing Applications That Consume Excessive CPU on Mac
When an app consumes excessive CPU, it may hang or stop responding to user input. Your best option is to force quit it. Press Cmd + Option + Esc to open the “Force Quit” dialog box.
A frozen app appears in red with the label “Not Responding.” Select that app and click “Force Quit.” If you’re dealing with an app that won’t respond to the Force Quit method or Activity Monitor fails to open, consult our guide on using Terminal to force quit an app.
A web browser is based on multi-process architecture. It includes all the logical functions in separate processes: the main (browser) process, GPU process, and dedicated process for each tab and extension.
To see this in practice, press Shift + Esc to open Chrome Task Manager and inspect its CPU + Memory usage.
By nature, a browser will use excessive CPU if you open too many tabs that display high-resolution photos and videos. Once you close the tab or delete unused extensions, CPU usage will be reduced.
Fix Kernel Task High CPU Usage
The kernel loads the core macOS foundation and essential drivers. “kernel_task” is the process that displays important metrics from the kernel. Its main purpose is to regulate the CPU temperature by making the processor less available to the processes.
In other words, if your CPU runs hot, the kernel gets activated to cool down your Mac. But in response, the CPU load of “kernel_task” spikes up. High CPU usage may indicate blocked vents, faulty temperature sensors, corrupt third-party kernel extensions, and incompatible hardware/peripheral devices.
On Intel Macs, you can:
- Reset the SMC (System Management Controller). It fixes a variety of problems on your Mac, including WI-Fi difficulties and dropped connections, and issues with the trackpad.
- Remove the third-party kernel extension. To see the installed kernel extension, launch System Information (About This Mac -> System Report) and navigate to “Software -> Extension Name.” Click the “Obtained from” column to see the loaded kext at the top.
The “kernel_task” process runs efficiently on Apple Silicon Macs because of the architectural change (System on Chip) coupled with kernel hardening and extensive core management (different cores running at varied frequency).
SMC is absent and there’s no need to reset NVRAM manually. Shutting down and restarting your Mac can solve most of your problems. However, certain workflows or factors can still trigger the kernel panic. In this case, you should consult the Apple Support team.
Reduce WindowServer CPU Usage
The main role of “WindowServer” is to draw windows into the display and manage them. Without it, there’s no GUI (user interface) to interact, and you have no control over it. It takes advantage of the built-in Metal GPU to manage transparency, UI composite, and render your windows quickly.
By default, WindowServer consumes 10% to 30% of your CPU and rarely causes any problems. If you’re experiencing high CPU usage, try these fixes.
- Quit your apps in a gradual manner and note the CPU usage. Restart your Mac and monitor the CPU usage. Once you’ve identified the culprit app, send a detailed log to the developer.
The WindowServer process is also responsible for managing multiple displays and even controlling their behavior. If the CPU usage remains high, follow these steps:
- Turn off screen sharing and separate spaces for your display.
- Remove the clutter from the desktop, as macOS considers every icon on the desktop as a window and burdens WindowServer more.
Cut Down Bird Process CPU Usage
“bird” is the backend process behind iCloud that activates when you start backing up files to iCloud Drive. When your files get synced, the CPU usage should be reduced. High CPU usage suggests that certain files have been corrupted, and iCloud cannot sync those files.
At the same time, you must take note of the “cloud” process related to CloudKit. Third-party apps can use CloudKit to move data between the apps and iCloud containers. Apple also uses CloudKit to sync your files in Desktop and Documents to other devices.
To solve this problem, we’ll temporarily disable iCloud to prevent the “bird” process from syncing files again.
- Open “System Preferences” and click “Apple ID.”
- Click on “iCloud” and untick “iCloud Drive.” When you do this, click “Keep a Copy” to create a folder called iCloud Drive (Archive) in your home folder.
- Tick “iCloud Drive” again to reactivate the “bird” process and recheck the CPU usage in Activity Monitor. You’ll have to move all of your files to the iCloud Drive manually.
Curtail Spotlight Indexing CPU Usage
“mds” and “mdworker_shared” are part of Spotlight and consist of two components: “mds” stands for metadata server, which manages your index to give you quick search results, and “mdworker” stands for metadata server worker and does all the hard work of indexing your files.
Both of these processes work in the background and maintain the databases of indexed metadata for each attached local volume. They never consume excessive CPU unless you’re copying files, say from an external hard drive to your new Mac.
You can prevent some folders or volumes from being indexed to reduce the CPU load. Navigate to “System Preferences -> Spotlight” and click on the “Privacy” tab.
- To add new items, click the “Add (+)” button and choose your item from the browser dialog. All Spotlight settings are applied immediately, and macOS deletes any indexed database from that volume.
- To rebuild the index, click the Remove (-) button at the bottom of the list.
Tip: read our guide on mastering Spotlight.
Frequently Asked Questions
Can I monitor CPU usage in the menu bar?
Activity Monitor does not let you pin selective stats to the menu bar. You can enable “Monitor → Show CPU Usage or History,” but it opens a new window. However, we suggest you try these menu bar apps for Mac that will show the complete details for CPU, Memory, GPU, Network, Disk, and more.
Stats is the macOS system monitor for your menu bar and supports 10.13 High Sierra or later. iGlance is a customizable system monitor menu bar that shows details like CPU utilization as a graph; reads CPU temperature; monitors fan speed, memory usage, network usage; and more.
Are there better tools than Activity Monitor?
Yes, but it’s a Terminal command called “top.” Launch Terminal and type in “top -u” to sort processes by CPU usage. Other than that, you’ll get the details of state of the processes, number of page faults, total number of page-in, process memory handling, and more.
If you use Homebrew for Mac, you can install htop to see the percentage of CPU consumption, state of the processes, priority, CPU time, and more. You can sort the processes and trace the absolute path to the processes.
Can a malware on your system consume excessive CPU?
Yes. It can happen if there’s unwanted crypto-mining malware running on your Mac. Inspect the LaunchDaemon folder and note any unknown configuration files. We also recommend running a thorough scan with Malwarebytes for Mac. Read our guide on detecting and removing malware from your Mac with Malwarebytes.
Image credit: Pexel. All images and screenshots by Rahul Saigal.
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