iMac 27" - Windows 7 64bit - screensaver not activating

Discussion in 'iMac' started by 1000, Mar 20, 2010.

  1. 1000 macrumors member

    Mar 20, 2010
    HI there all, this is my first post and I'm fairly new to all things Mac so please bear with me.

    I purchased a lovely 27" iMac yesterday. I have installed Windows 7 64bit on it and apart from a few quirks everything is running very well.

    One thing that is bothering me is the Windows7 screensavers and power-management... they never activate. The power-saving features of Windows 7 don't seem to work at all. I did an install using the new "late 2009" drivers on a USB thumb drive during installation of Windows 7 so I think I've done everything properly.

    Is there something else I need to do in order to access Win7's power management features ?

    Also, I've noticed that the Mac drivers for the ATI 4850 onboard graphics do not offer me the full range of resolutions (there are only a few options at the moment, the full native res, 1280x720, 1920x1080 and 800x600). How do I get access to the full range of resolutions ? Can I install ATI Radeon drivers and use those instead of the Apple supplied drivers ?

    Cheers and thanks in advance.

  2. 1000 thread starter macrumors member

    Mar 20, 2010
    I figured it out (sort of).

    If I plug anything into the headphone/sound out jack at the back of the MAC the power management features are disabled. When I remove the jack, the power management features work fine.

    In addition, when I have anything plugged into the jack the CPU usage runs up to 40%. When I unplug it the CPU usage returns to 0-1%.

    Can anyone say "stupid bug" ?

  3. Hellhammer Moderator


    Staff Member

    Dec 10, 2008
    Install Bootcamp drivers from the install disk that came with your iMac
  4. 1000 thread starter macrumors member

    Mar 20, 2010
    I HAVE installed bootcamp 3.0 and then I also installed 3.1. The headphone jack wierdness is now my only issue.

    The speakers in the MAC are balls and I definitely need external speakers and subwoofer so the question remains when Apple will fix the problem with the headphone jack CPU usage etc.

  5. 1000 thread starter macrumors member

    Mar 20, 2010
    OK, I've fixed the headphone CPU usage after a little more research. You plug the jack in, the CPU usage rocks to 40% and THEN you remove the jack ever so slightly from the socket. The CPU usage goes back to normal and power management works and you can still hear the sound perfectly through the speakers.

    Talk about quirky..


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