How can "%" of CPU be more than 100?

Discussion in 'macOS' started by Richard1028, Oct 7, 2009.

  1. Richard1028 macrumors 68000

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    Jan 8, 2009
  2. firestarter macrumors 603

    firestarter

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    Green and pleasant land
    #2
    Each cpu core is up to 100%. So with a dual core machine you get up to 200%. My MacPro gets up to 800%...
     
  3. PlaceofDis macrumors Core

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    Jan 6, 2004
    #3
    correct. its confusing, and its not like a core is its own processor; thus making things really weird.
     
  4. Richard1028 thread starter macrumors 68000

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    Jan 8, 2009
    #4
    Ah, got it. But wouldn't it make more sense for activity monitor just to divide by "2" on a dual core (since precent implies a limit of 100?)
     
  5. firestarter macrumors 603

    firestarter

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    #5
    Maybe - but if you go over 100% then you can see that the app is multithreading and using multiple CPUs.

    Given that most computer CPUs these days are a similar speed (2 to 3GHz) and more power usually comes from having ore CPUs, the % rating is also quite a good measure of relative speed.

    There's probably some marketing in here too...
     
  6. whooleytoo macrumors 603

    whooleytoo

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    Aug 2, 2002
    Location:
    Cork, Ireland.
    #6
    Either way is good..

    One thing I like about this way is if a process is unresponsive in OSX, Activity Monitor shows it using 100% CPU and so is readily identifiable. On Windows, it's at 25% (on a quad core machine) or 12.5% (on an octo core) so it's not as obvious.

    Since many processes execute only on one core/processor, I think it makes sense to specify that process' CPU usage just in terms of that core.
     
  7. Catfish_Man macrumors 68030

    Catfish_Man

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    Sep 13, 2001
    Location:
    Portland, OR
    #7
    Actually it basically is. A two processor machine and a two core machine are identical for virtually all uses. The only real differences one could measure are in bus/cache contention.
     

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