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Helpful answers
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Jun 8, 2014 4:09 PM in response to bengmugenrby BobHarris,★HelpfulMultiple CPUs (cores) and an app having multiple execution threads, means each available CPU could be used in part or 100% for a sum in the Activity Monitor display greater than 100%.
Firefox is is a multi-threaded app.
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Jun 10, 2014 1:09 AM in response to BobHarrisby bengmugenr,Thanks for your explanation.
But it is interesting that I never observed the same on my Mac Pro mid 2012. Secondly, in my understanding, the %CPU should be an overall percentage of all processors or cores as commonly there is no point show a single CPU's performance and ignore the others.
Am I correct?
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Jun 10, 2014 5:36 AM in response to bengmugenrby BobHarris,It all depends on what is reporting the CPU usage, and whether they want to count all cores and hyperthreading as fraction of 100% or if each thread of exection can consume 100% of a core or hyperthread.
If you look at your own Activity Monitor screen shot you can see that mds is using 20.7%, so even if Firefox was listed as using "Just" 100%, the sum of Firefox and mds would be 120+% so you are still over 100%. Thus Activity Monitor is allowing each core and hyperthread to have its own 100%.
A different reporting service may count things differently.
Anyway, depending on how many cores your Mac has AND whether the chip supports hyperthreading will determine Whether you have 200% (dual core no hyperthreading), 400% (quad core no hyperthreading), 800% (quad core with hyperthreading), 1600% (8 core with hyperthreading), etc...
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