I have had crazy high kernel task CPU usage levels with my Macbook Pro 15", 2015, fully maxed with 16 GB RAM.
I thought the following could be culprits:
Using a 4k external screen and a cinema display for three total screens.
Too many Chrome extensions.
However, the problem might be none of these. I think I’ve tracked down the issue to Spotlight indexing my software development directories. So I’ve added any development related directories to the Spotlight exclude list.
This article describes how to prevent these folders from being indexed by Spotlight.
Given my heavy usage of RubyGems and NPM, and having zillions of development related files, this was likely the issue of my Mac becoming almost unusably slow.
I also like this tip of changing the default view for the Finder from “All Files” (which is insane for a software developer).
Here are a few more helpful links:
I also moved my Apple mail file over to an external drive. That saved about 50GB of space!
Probably, It’s not the best solution for developers - but I’ve bought CleanMyMac and I’d like to report that this program works really nice, it can find a lot of abandoned configs and caches and clean it. Sometimes I can free up to 30Gb because of old and unnecessary files.
Out of all the suggestions, I did the exclude-folder from Spotlight and my machine has been noticeably better since then. Only been two days, and I haven’t done a lot of heavy development since then. I think CPU has been recovering much better than before.
Thanks for sharing the ways to fix Mac running slow issue. They are so great！My Mac computer has just updated its operating system recently. And I found out its running speed slow down and even get stuck sometimes. My friend have told me some methods on how to uninstall programs on Mac to free up the space of Mac before. Now I am so glad to get more solutions here.