System: MacBook Pro 13" 2017 2.3 GHz Intel Core i5, 16 GB RAM, Intel Iris Plus 640 in clamshell mode on Mac OS X 10.14, connected to LG UltraFine 5K via USB-C.
Issue: kernel_task high CPU usage, sluggish system speed.
Description: The system runs fine, until at some point kernel_task begins to take up a majority of CPU usage. This in turn causes the system to slow down significantly and the fans to speed up.
There are various solutions to kernel_task issues floating around on the net, yet none of the solutions were able to solve this particular problem. The issues were present regardless of light or heavy usage — in combination with the 5K monitor, it was only a matter of time until the computer would become sluggish.
Solution: After quite some trying I realized that Night Shift is the cause. It turns out that the issue occurs during Night Shift’s transition phases. If you experience the same issues, give it a try: open up Activity Monitor, and head over to System Preferences -> Monitors to switch off Night Shift. The kernel_task process should calm down immediately. However, I enjoy the Night Shift feature and would love to keep using it. Until a fix is provided, I am using Flux again. An alternative is to switch Night Shift on and off manually. For now, and despite Flux being enabled, the kernel_task process has been behaving as desired. The system runs smoothly and the fans keep quiet.
Issue: kernel_task high CPU usage, sluggish system speed.
Description: The system runs fine, until at some point kernel_task begins to take up a majority of CPU usage. This in turn causes the system to slow down significantly and the fans to speed up.
There are various solutions to kernel_task issues floating around on the net, yet none of the solutions were able to solve this particular problem. The issues were present regardless of light or heavy usage — in combination with the 5K monitor, it was only a matter of time until the computer would become sluggish.
Solution: After quite some trying I realized that Night Shift is the cause. It turns out that the issue occurs during Night Shift’s transition phases. If you experience the same issues, give it a try: open up Activity Monitor, and head over to System Preferences -> Monitors to switch off Night Shift. The kernel_task process should calm down immediately. However, I enjoy the Night Shift feature and would love to keep using it. Until a fix is provided, I am using Flux again. An alternative is to switch Night Shift on and off manually. For now, and despite Flux being enabled, the kernel_task process has been behaving as desired. The system runs smoothly and the fans keep quiet.
