Activity Monitor reporting >200% CPU on a 2-core system?

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Level 2

303 points

Activity Monitor reporting >200% CPU on a 2-core system?

I'm trying to get a feel for the relative performance of my current Macs against other options/purchases.

For that, I need to know what is important for the software I run and if it actually helps more for that software to have the highest single-core performance or multi-core performance. The software I'm most interested in is Adobe InDesign (seems single core at first glance) and Parallels Desktop.

So, while trying to get some feeling for this, I downloaded and ran Geekbench 4 and looked at what Activity Monitor was telling me. Several activities (especially during the first single-core tests) did not get AM over 30%, but when it was doing multi core (on my 2core i5) it regularly reported more than 200%. Now, I think 100% is a single core, so both values (single core staying well below 50%, and dual core going over 200%) make much sense.

So, are there better ways of finding out how software actually behaves on my CPU?

MacBook Pro with Retina display, macOS Sierra (10.12.4)

Posted on Jun 17, 2017 4:03 AM

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Answer 1

Gerben Wierda Author

Level 2

303 points

Jun 17, 2017 9:58 AM in response to Rudegar

I was not talking about total CPU but (the values in the table for) per process CPU%.

The System/User/Idle are percentages that add up to 100% (type of cpu). The table shows per process how much cpu is being used. Example:

%CPU in that table seems to be per-core but can display a value more than 100% times the number of cores.

G

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Answer 2

Rudegar

Level 10

180,186 points

Jun 17, 2017 7:05 AM in response to Gerben Wierda

no and nor do windows

many computers today have 4core cpu which support hyperthreating which result in 8 logical cores

so going over 100% of cpu usage would make no sense, % is of total cpu usage not of how much % of each logical or physical core / cpu

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Answer 3

Gerben Wierda Author

Level 2

303 points

Jun 17, 2017 7:51 AM in response to Rudegar

Well, except that Activity Monitor (which is what my question is about) apparently counts a 1 core as 100% cpu, so 400% is full use of 4 cores. It makes perfect sense, it's just a different standard. %cpu means %core here.

But what surprised me was that under that standard, and without hyperthreading, Activity Monitor reports more than (number of cores) x 100%. That makes no sense indeed.

And using Windows to see how my Mac apps behave is in any case not an option.

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Answer 4

Rudegar

Level 10

180,186 points

Jun 17, 2017 8:47 AM in response to Gerben Wierda

on my imac activity monitor does not and I only mentioned windows because task manager in windows display it the same way as activity monitor on osx does

in such programs Idle display the unused cpu power and currently my 8 logic core setup display

system 0.7%%

user 1.30%

Idle 98%

a full 100% total

of cause that being said does not mean one can't setup activity monitor to display it differently then it does for me.

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