CPU load and %CPU don't add up in Activity Monitor

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Level 1

8 points

CPU load and %CPU don't add up in Activity Monitor

Hello,

I'm troubleshooting an issue with an application. When I look at Activity Monitor, the first three processes add up to over 100% yet my System and User levels are are only about 25%. Please explain why the sum of the Processes doesn't add up to the amount being used by the System and User. I am using macOS Monterey with a 2019 iMac but this was the same in previous OS versions.

Thanks,

iMac 27″, macOS 12.0

Posted on Nov 1, 2021 1:11 PM

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Answer 1

lllaass

Level 10

210,513 points

Nov 1, 2021 1:33 PM in response to cdamaden

Because 100% is 100% on one core. If you have more than one core, total CPU can be as high as 100 times the number of cores

https://www.intego.com/mac-security-blog/how-to-use-activity-monitor-to-troubleshoot-problems-on-a-mac/

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Answer 2

cdamaden Author

Level 1

8 points

Nov 1, 2021 6:06 PM in response to lllaass

Thank you - that resolves my question. I understand the answer but find apple's labeling convoluted. Isn't the CPU composed of the cores? If I have 4 cylinders in my engine and the measure is % engine then most people would say 25% engine is not 25% of one cylinder.

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CPU load and %CPU don't add up in Activity Monitor

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