So you found something called “kernel_task” in Activity Monitor, and you want to know what it is. Good news: it’s nothing nefarious. It’s actually your operating system.
A “kernel,” if you didn’t know, is at the core of any operating system, sitting between your CPU, memory, and other hardware and the software that you run. When your turn on your Mac, the kernel is the first thing that starts, and basically everything you do on your computer flows through the kernel at some point. Activity Monitor puts all of this varied activity under one banner: kernel_task.
If you’re computer isn’t running slowly, don’t worry about this process taking up a lot of memory or occasionally using up CPU cycles: that’s normal. Unused memory is wasted memory, so kernel_task will put it to work for things like caching files, and running a modern operating system means sometimes using some CPU power.
But if kernel_task is constantly using a majority of your system resources, and your Mac is really slow, you might have a problem. Restarting your Mac is the only way to restart your kernel, and sometimes that will solve all problems. But if the behavior persists, here’s a bit more information.
kernel_task Pretends to Use CPU Cycles To Keep Things Cool
If you’re doing something that takes up a lot of processing power—converting 4K videos, say—you might wonder what’s taking so long and look at the Activity Monitor. Often you’ll see kernel_task is using up a lot of CPU power…power which you’d rather that power be used by your intensive process.
It’s understandable if you’re frustrated, but it turns out your operating system is doing this on purpose to prevent your CPU from overheating. To quote Apple’s support page:
One of the functions of kernel_task is to help manage CPU temperature by making the CPU less available to processes that are using it intensely….