Process Using CPU Over 100%?

Discussion in 'iMac' started by dgrizzell, Jul 12, 2011.

  1. dgrizzell macrumors member


    Jul 10, 2008
    Nashville, TN
    I was encoding an HD video today on my new iMac and was curious as to how well the processor was handling all the data. I checked the thread in activity monitor and noticed that the "% CPU" was reading over 100% and sometimes 200%. How does this work? I have a basic understanding of computer science but how does something run beyond 100% efficiency continuously like that without taking damage?
  2. Intell macrumors P6


    Jan 24, 2010
    One core of the mult-core CPU is 100%, 2 cores are 200%, ect.
  3. mrfoof82 macrumors 6502a

    May 26, 2010
    Lawton, OK
    To be even more specific, this also applies to virtual cores. On an i7-equipped iMac, it's certainly possible for processes to approach 800% CPU utilization. I know HandBrake (thankfully) usually hangs around between 680% and 760% utilization for me.
  4. PaulKemp macrumors 6502

    Jun 2, 2009
    Is there a way to limit these applications? Specially apps like Handbrake and Plex Transcoding that uses so much.

    I dont mind my CPU doing its job, but I do mind hearing fans in my living room.

    edit: Ive looked at CPUTrottle, but that is PID based, and the PIDs change from one time to the next. I need something that uses the name of the application, and one session or instance can not use more than 50%
  5. stridemat Moderator


    Staff Member

    Apr 2, 2008
    Not that I know of. I do all my converting at night for that very reason.
  6. Lucas Godfrey macrumors 6502

    Lucas Godfrey

    Jul 12, 2010
    Somewhere between Here and There
    Don't worry, in over a year of heavy use I've never even heard my iMacs fans. The top and back get hot mind you, but the fans have always been quiet.
  7. PaulKemp, Nov 19, 2012
    Last edited: Nov 19, 2012

    PaulKemp macrumors 6502

    Jun 2, 2009
    I wouldn't mind it if they were quiet, the problem was the sound! :) Note that this is a Mac Mini i7 2011, not the iMac.


    I've reached out to the developer of CPUTrottle, it's a good little application, but as of now, you can only limit one PID. So, the problem in my case, is that Plex transcoding one movie has one PID, the next transcoding session has another. So in it's current version the applciation doesnt fill my needs.

    The dev have however said that he might add some extra functionality, a GUI and maybe sell it on the app store. So this could be features coming in the near future!


    edit: Also, the most current beta build of Plex Media Server (PMS) has fixed the insane CPU usage. Im using the bought version PMS

Share This Page