How to fix kernel_task high CPU usage on Mac

7 min read

We like Macs because they are dependable and work for years without any servicing, whether on the hardware or software side.

Thanks to the App Store, all apps update automatically, including the macOS itself. FileVault keeps your data encrypted; firewall prevents unauthorized incoming connections; and sandboxing guards essential system data from third-party apps. 

There are a lot more security and safety features built into Macs that most users don’t even think about but that are designed to provide a smooth user experience. One of those features is the kernel_task Activity Monitor process.

What is a kernel_task process?

If you open Activity Monitor (from the Applications ➙ Utilities folder), you might see a kernel_task process somewhere high up on the list. But what is kernel task on Mac?

The kernel is the heart of the macOS. It’s the first process to come alive when you boot your Mac as it takes care of all the essential functions that allow for everything else to work properly. 

For example, the OSX kernel_task high CPU usage allows it to regulate your Mac’s temperature.

activity monitor high cpu mac

Why is kernel_task hogging CPU?

When you’re working on resource-intensive tasks, having plenty of CPU available for processing them is important. But you might see that most of the CPU on your Mac is consumed by kernel_task. Why is that? 

When you see kernel_task Mac high CPU that means your Mac is running hot and trying to protect itself from damage due to heat exposure. 

Heat exposure might be external. You might be in a hot environment with poor ventilation. The fans on your Mac might not work properly and limit cooling. Or your Mac might be too hot due to handling too many connections, such as external monitors, USB peripherals, SD cards, and charging cables. 

Another reason for your Mac getting hot are internal processes. If you’re trying to perform heavy tasks like video editing or 3D rendering without giving your Mac enough breaks to cool down, it’ll start overheating. 

You can track the MacBook kernel_task high CPU issue manually with Activity Monitor, but that would require constantly opening the app to check on it. A much easier solution is to use a continuous Mac monitoring solution like iStat Menus.

iStat Menus is the most comprehensive Mac monitor to date. It tracks every aspect of your system right from the menu bar, whether it’s CPU, GPU, RAM, disk usage, heat sensors, network, or anything else. 

istat menus cpu monitor mac

You can customize the exact data you want to see in iStat Menus (e.g. kernel_task CPU or internal temperature) and hide everything else.

How to fix kernel_task high memory and CPU consumption

When macOS kernel_task high CPU issues appear, it takes up a lot of processing power that could be used by other apps to do the work you want to do. 

So how can you limit the amount of CPU that kernel_task is using? There are a few ideas: 

  • Restart your Mac
  • Update your macOS
  • Check your Mac for malware
  • Stop idle processes
  • Reset SMC on Mac
  • Reset NVRAM on Mac
  • Optimize your Mac charging

Restart your Mac

When your Mac runs hot and OSX kernel_task high CPU usage is apparent, restarting your Mac can help. 

Restarting your Mac decreases the number of tasks, frees up RAM, and helps process the remaining tasks more efficiently. It’s one of the easiest fixes available to any Mac user.

To restart your Mac, click the Apple icon in the menu bar and select Restart.

Update your macOS

Keeping your macOS up to date not only provides your Mac with new functionality but also solves any potential security issues and fixes outstanding bugs, of which macOS kernel_task high CPU usage could be one. 

It’s recommended to keep macOS updates automatic and regularly check if there are any updates available that haven’t yet been installed. To do both: 

  1. Go to System Settings
  2. Navigate to General ➙ Software Update
  3. Toggle on “Automatic updates” 
  4. Install any new updates that are available

update your macos

Check your Mac for malware

While malware is not as big of an issue on Mac as it is on Windows, it’s still recommended to scan your Mac for any viruses regularly, as they might affect your Mac’s performance and kernel_task Mac high CPU usage in particular.

The most comprehensive way to check your Mac for malware is to use CleanMyMac X. 

CleanMyMac X is the world’s most powerful Mac optimization app. In just a few clicks, you can clean, speed up, and protect your Mac without getting into any unnecessary technicalities. You can also use CleanMyMac X to install updates and delete software, find large unused files and folders, and protect your privacy. 

To scan your Mac for malware with CleanMyMac X: 

  1. Launch the app
  2. Navigate to the Malware Removal tab
  3. Click Scan
  4. If any malware was found, click Remove

cleanmymac x scan malware mac

Stop idle processes

If your Mac is running too many processes at once, it will start to heat up and call on the kernel_task for help. The good thing is, most Mac users have lots of idle processes that could be stopped to free up resources and cool down your Mac without affecting anything else. 

One way to stop idle processes is to use Activity Monitor:

  1. Open Activity Monitor
  2. Switch to the Memory tab
  3. Sort all processes by the amount of RAM they consume
  4. Stop any processes you recognize and don’t need by clicking the Stop icon in the toolbar

activity monitor stop idle processes

A more advanced solution for stopping idle processes and freeing up your Mac’s resources is App Tamer. 

App Tamer is a powerful task-monitoring solution that lives in your menu bar. It shows all active processes ranked by their CPU usage and lets you stop any of them in one click. One of the key App Tamer features, however, is the ability to throttle processes when they exceed a given CPU percentage (e.g. 15%). That way, you can keep more processes going at once but set restrictions on them, so none take over all the CPU power. 

app tamer restrict cpu mac

To limit the amount of CPU apps can use: 

  1. Launch App Tamer
  2. Click on a specific app
  3. Check “Slow down this app if it uses more than” 
  4. Use the slider to pick the right CPU max

Reset SMC on Mac

Your Mac might be heating up if its fans aren’t working properly. The component responsible for controlling your Mac’s fans, battery, keyboard, and other hardware is called SMC (system management controller). Resetting it might help the fans work better and cool down your Mac, removing the need for kernel_task to step in. 

To reset SMC on Macs released after 2018 (with the T2 security chip): 

  1. Turn off your Mac
  2. Hold Control + Option + Shift for 10 seconds
  3. Hold the power key without releasing the others for another 10 seconds
  4. Release all keys and turn on your Mac

Reset NVRAM on Mac

Another important component responsible for storing particular system software and hardware settings is NVRAM (non-volatile random access memory). 

Resetting NVRAM can help clear out any bugs that might be present in certain hardware configurations. 

To reset NVRAM: 

  1. Shut down your Mac 
  2. Turn the Mac back on
  3. As soon as you hear the startup chime, press and hold Option + Command + P + R until your Mac restarts

Optimize your Mac charging

If you find that your Macs heats up from charging, try plugging the charging cable on the right side. People found that charging on the right doesn’t tend to produce as much heat. In addition, avoid charging your Mac while you have an external monitor plugged in. If possible, pick one or the other.

As you can see, your Mac needs kernel_task to operate, and seeing macOS kernel_task high CPU usage just means that your Mac is trying to protect itself from overheating. You can easily monitor the kernel_task process and your Mac’s internal temperature with iStat Menus. CleanMyMac X can help find any malware. And you can use App Tamer to limit how much CPU any given process consumes.

Best of all, iStat Menus, CleanMyMac X, and App Tamer are available to you for free for seven days through the trial of Setapp. Setapp is a curated collection of more than 240 top-rated Mac and iOS apps across all categories, from finance to web development. Try every Setapp app at no cost today and find better solutions for your daily tasks.


Is it safe to quit kernel_task?

Do not quit kernel_task from Activity Monitor. It supports Mac’s vital processes and killing it might lead to various unpredictable bugs. Best case scenario, your Mac will simply restart. 

Why is kernel_task running on my Mac?

The main function of kernel_task is to ensure that vital processes operate smoothly on your Mac, including temperature regulation. It’s the first process that starts when you boot your Mac, and it never stops.

Is kernel_task malware?

No, kernel_task is an essential macOS process that controls all the main features of the operation system.

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