Disabling Cores

Discussion in 'Mac Pro' started by packsherpah, Feb 8, 2011.

  1. packsherpah macrumors newbie

    Jul 19, 2010
    I have a situation where I need to disable some cores to make a particular application work (better). I have a Mac Pro, but this particular app only runs in Windows. I am running windows 7 in bootcamp on a 12 core 2010 Mac Pro. If this was a PC, I would go into the bios and at the bios level disable the cores then boot into windows with fewer cores. Is there any way I can accomplish this type of thing on a Mac Pro using bootcamp? I know there is no Bios, so how else can I disable some of the hardware for the windows 7 environment?

  2. FroColin macrumors regular

    Jun 4, 2008
    Why on earth would disabling cores give you better performance on a particular application?
  3. ndraves macrumors member

    Jan 19, 2011
    I haven't looked into it much but can't you decide in parallels how much 'hardware' you give the VM.

    If this is the case can you not just reduce the number of cores available to windows 7?
  4. gglockner macrumors 6502


    Nov 25, 2007
    Bellevue, WA
    Are you talking about hyperthreading? There are some cases where hyperthreading makes things run slower. Unfortunately, there is no BIOS, so you cannot disable hyperthreading while booting into Windows. It's possible to disable hyperthreading in Mac OS X, but this would only apply if you're running Windows via virtualization (Parallels or VMWare).
  5. initialsBB macrumors 6502a

    Oct 18, 2010
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    I once met someone using bootcamp who told me there existed a utility for Windows that would disable cores without going into BIOS. He also had an old piece of software that would not run when more than 2 cores were present.

    Unfortunately I cannot for the life of me find the name of the utility, but I know it exists.
  6. Cindori macrumors 68040


    Jan 17, 2008
    you can disable cores, and HT, using this utility.


    EDIT: this is a OSX utility, it will not apply for Windows unfortunately

    for Windows, I recall you can select which cores the process should run on if you enter Task Manager (or Activity Monitor, w/e its called... the ctrl-alt-delete thing)

    this required a Pro edition of the Windows, at least in the Win XP days
  7. cutterman macrumors regular

    Apr 27, 2010
    Yes- go to process list, right click and select "set processor affinity"

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