Mac slow mac
2 tested guides, grouped by what is actually going on. Covers: Beachball, high CPU, kernel_task, WindowServer.
Short answer
- kernel_task is part of macOS; one of its jobs is to keep the CPU from overheating by taking CPU time away from busy apps.
- High kernel_task CPU is a symptom of heat, not the cause, so quitting or killing kernel_task is not possible and would not help.
- Open Activity Monitor, sort by % CPU and quit the app that was using the most CPU before kernel_task went up.
- Then remove the heat: clear the vents, use the Mac on a hard surface, and check whether a charger or external display is adding load.
Start here
kernel_task using high CPU on Mac: what it means and what to do
kernel_task takes CPU time to cool the Mac down, so it is a symptom, not the cause. How to find what is heating the Mac and bring kernel_task back down.
High CPU
- WindowServer high CPU on Mac: why it happens and how to lower itmacOS 26.3 Tahoe