iMac CPU 350%, iMac glacially SLOW

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Piccoletto Author

Level 1

4 points

iMac CPU 350%, iMac glacially SLOW

macOS Monterey Version 12.4

iMac19,1

32GB RAM

My GLACIALLY SLOW iMac has me at my wit's end.

When checking Activity Monitor, SOMETHING is always taking up around 350% to 400% of the CPU. Sometimes it's kernel_task. Other times it's mds_stores. And other times, it's WindowServer.

I tried a bunch of “fixes” that didn't work, so finally I decided to wipe my hard drive and reinstall a fresh copy of macOS Monterey.

(I then manually copied over my Documents with drag and drop. I did NOT copy anything from either Library folder. I didn't install any fonts, just Photoshop and a few browsers.)

Two days after doing this, the problems returned, only worse. It used to take around an hour for the problems to appear, but now they occur immediately after booting up... with no applications running!

Here are some of the things I've tried:

Reset PRAM/NVRAM
Reset SMC
Ran Disk Utility from Recovery (no problems found)
Checked the CPU temp via Terminal command (from 64°c up to 76°c)
Booted into Safe Mode (CPU usage still WAY off the charts)
Read every thread about the topic on this forum (nothing helped)

My poor iMac is so slow at times that it's barely usable.

Is there anything else I can try to fix this nightmare?

PS: I've noticed people here paste their EtreCheck results. Here are mine:

https://pastebin.com/bmnH4ZKu

THANK YOU!!!

iMac

Posted on Jul 18, 2022 9:14 PM

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Answer 1

Best reply

Piccoletto Author

Level 1

4 points

Jul 20, 2022 12:53 AM in response to Piccoletto

After months of dealing with this problem, I finally got it fixed!

While searching for a solution, I've come across posts from many other people suffering from the same problem, so I hope that someone sees my post here and benefits from it.

Above, BobHarris mentioned overheating. My iMac's vents were 95% clean, but this got me thinking.

Very long story short, I downloaded an app called TG Pro. What it does is allow you to set your Mac's internal fans to come on at a lower temperature than they normally would.

I installed the app, pretty much using the default settings, and all of my Mac's problems DISAPPEARED. Gone, just like that. Months of suffering put to an end simply by launching an app.

I waited an entire day before posting this, just to make sure the problems were gone for good, and my iMac is still running better than it ever has before.

Now instead of my iMac choking if I use Firefox or Photoshop, I can run both simultaneously... and ALSO watch a 4k video, run MS Word, run Slack, and more, all at the same time... and Activity Monitor never goes above one or two bars!

I know this sounds like an ad, but I assure you, it's not. There are other apps that do the same thing, such as iStat Menus and Macs Fan Control.

After months of trying to get this problem fixed, I can't believe the solution was so simple!

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Answer 2

BobHarris

Level 9

53,795 points

Jul 19, 2022 5:26 AM in response to Piccoletto

kernel_task using 100’s percent CPU means your CPU chip is overheating and kernel_task is putting it into a low power mode idle so it will cool down.

If kernel_task is using a large percentage of your Mac CPU - Apple Support (UG)

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Answer 3

Piccoletto Author

Level 1

4 points

Jul 19, 2022 11:10 AM in response to BobHarris

Thanks for your response, BobHarris.

As mentioned in my post above, the temperature of my iMac at the time of these occurrences was between 64°c and 76°c - is that hot enough to cause such problems?

Also, there are times when kernel_task is not the problem. About a third of the times, it doesn't show up in Activity Monitor at all...

Sometimes it's kernel_task. Other times it's mds_stores. And other times, it's WindowServer.

That said, I just gave the vents on my iMac a good cleaning, and will see if anything improves.

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iMac CPU 350%, iMac glacially SLOW

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