Parallels: Crazy fan speed/CPU usage

Discussion in 'Windows, Linux & Others on the Mac' started by FullmetalZ26, Nov 30, 2006.

  1. FullmetalZ26 macrumors regular

    Jun 12, 2006
    I recently installed Parallels on my Macbook, and whenever it's running one core's system usage goes up to 100%, which kicks the Macbook's fan on full blast in less than 2 minutes. I can understand there being a heavier load while running, say, Windows 2000 or XP, but this is happening with DOS 6/Windows 3.1 running in the VM. I can't see how running software designed to comfortably run on a 386 could be taxing a Core Duo. This is more than a little annoying, seeing as it makes it impossible to play a quick game of Rodent's Revenge or Centipede in class without getting several inquisitive/annoyed stares. Have I made some gross oversight somewhere, or are there some settings I overlooked somewhere, or....? Thanks for any help.
  2. Thomas Harte macrumors 6502

    Nov 30, 2005
    The problem is exactly that the software is designed for a 386 and not something more modern. Parallels is in the business of giving running OSs as much processor time as they request. Windows 3.1 and MS-DOS come from a time before OSs would put the CPU to sleep while not using it. So they both want to use 100% of your CPU, and Parallels lets them. Conversely more modern OSs such as Windows 2000 and onwards are clever enough to know about CPU sleep and should use much less CPU time on your machine. Sadly Parallels doesn't know how to set a maximum CPU usage for its hosted OSs, so I don't think there is anything you can do about this.

    Not exactly what you're asking, but have you checked out DOSBox? You can get a universal binary from here and it should be able to run most old DOS games, albeit not as many as Parallels. And I think you're possibly out of luck for Windows 3.1.
  3. FullmetalZ26 thread starter macrumors regular

    Jun 12, 2006
    Didn't think about it that way, makes sense... I just finished installing 2000 in Parallels, so I suppose I'll move all those ancient MS Arcade games over there and see if they want to cooperate. Thanks for the DosBox suggestion too, I'll give it a try.

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