Linked Questions

20 votes
6 answers
29k views

kernel_task consumes 500% CPU on AC power, sometimes [duplicate]

Typically, my kernel_task process uses 1-4% CPU and 100-700MB of memory. However, sometimes when I have the power adapter plugged in, the CPU usage jumps to around 500% (8 cores) and stays there until ...
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  • 1,110
6 votes
1 answer
3k views

Mac book pro 16 slows down completely when connected to an external monitor [duplicate]

I have a Macbook Pro 16" and recently purchased a 24" (HD) Dell monitor via HDMI (via a USB-C to HDMI converter) After about 20m of usage, my mac comes to a crawl and really slows down. It ...
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  • 449
1 vote
0 answers
56 views

CPU constantly hot with low usage [duplicate]

My 2019 16" MacBook Pro with 2.6GHz 6-core i7 processor on macOS 11.3.1 is constantly running hot at ~60°C even when the CPU usage is only 8-10%. I've checked the ActivityMonitor, but no app is ...
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169 votes
11 answers
188k views

WindowServer high CPU on Yosemite

This is a follow up to So my Yosemite install is slow - what to do? Since installing Yosemite a week or so ago my machine is very sluggish. I am a web developer so I change windows/apps a lot. ...
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  • 2,278
40 votes
14 answers
43k views

Why is kernel_task using so much CPU?

I have a Macbook Pro Retina with the following hardware: Model Name: MacBook Pro Model Identifier: MacBookPro11,1 Processor Name: Intel Core i5 Processor Speed: 2.4 GHz Number of Processors: 1 ...
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32 votes
10 answers
21k views

CPU usage is too high with Yosemite and an external monitor

I use Yosemite 10.10.4 on my MacBook Pro (2012). I used to work with an external monitor: Apple Thunderbolt 27" monitor. The issue is that, according to Activity Monitor, the kernel_task process ...
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  • 479
36 votes
3 answers
60k views

What exactly does kernel_task do?

I'd just like to know what it is that kernel_task is responsible for. Also, what's an acceptable maximum RAM and CPU use for it?
user avatar
  • 14.5k
19 votes
4 answers
14k views

macOS artificially restricts speeds to 100 Mbps over Ethernet

Overview I have a 1 Gbps connection via a Cat 6 Ethernet cable to my MacBook Pro (16-inch, 2019). I am on macOS Big Sur 11.6 on the Intel Core i9 if that helps. The Ethernet cables connect to the ...
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  • 449
14 votes
3 answers
8k views

kernel_task hundreds of % CPU yet cpu frequency is being lowered

I'm trying to solve the mystery of a crazy high cpu usage on kernel_task. MacBook Pro (Retina, Mid 2012), 2.7 GHz Intel Core i7, Yosemite 10.10.2 I saw some advice to download the Intel Power Gadget....
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2 votes
2 answers
18k views

Are these normal temperatures?

I just got a new MacBook Pro 2017 128GB no-touchbar, bought it in the refurb. I'm doing a bit of Photoshop ( I know it's not the best MBP, but I really need it right now for work ) and I have Safari (...
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2 votes
3 answers
3k views

High CPU usage by system

I'm having by time to time problems with my OS running really slow because the System uses a lot of CPU (it stays like this ~30min). I've checked different articles on the internet in regard to this ...
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1 vote
1 answer
6k views

Macbook slows down when connected to external monitor and power supply

I have a Macbook Pro (Retina, Mid 2012) with the following configuration: 2.3 GHz Quad-Core Intel Core i7, 8 GB 1600 MHz DDR3, Intel HD Graphics 4000 1536 MB I use Dell P2419H as my external monitor ...
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6 votes
1 answer
2k views

Macbook Pro 2019 overheating with external monitor

Problem My Macbook overheats insanely. After investigating a bit, I found out that the correlation is extremely strong with having it plugged in to an external monitor with the Macbook Pro monitor ...
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  • 171
4 votes
0 answers
2k views

MacBook 2020 constantly disconnects USB 2.0 devices

The Problem Since I got my new Macbook Air 2020 (with i5 Upgrade), I encounter a strange and annoying problem every day: The MacBook suddenly looses connection to my USB devices. Namely my external ...
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1 vote
2 answers
1k views

MacBook Pro 16" running hot

I have a MacBook Pro 16 inch base model. I am a programmer, which means that it is running hot when I am working. When I am working it is between 70-80 degrees celsius, but when I open activity ...
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