3D performance suddenly sucks, PCI Express Link Width stuck on 1x

Discussion in 'MacBook Pro' started by LoneWolf121188, Jan 26, 2008.

  1. LoneWolf121188 macrumors 6502a

    Joined:
    Jun 7, 2007
    Location:
    Longmont, CO
    #1
    I was running Flight Sim X on my MacBook Pro (running Vista) last weekend after doubling my RAM (4GB FTW!) and everything was going great. I noticed a HUGE increase in speed, and I was able to pull 25fps or so with most settings all the way up. Life was good.

    Three days later, I boot back into Vista to do some more simming. Don't mess with anything, just load FSX after Vista finishes loading up. I run the exact same mission that I was doing before...and everything just grinds to a halt. I was getting literally <2 fps. WTF? I reboot, thinking its some random weirdness. Lo and behold, it does it again. I check everything in the nVidia control panel, power management settings, everything I could think of. Nothing changed.

    After some help from another forum, I realized that my PCI Express Link Width is stuck on 1x and won't throttle up when needed. Not having a BIOS to work with, how can I change this manually or otherwise force it back up to 16x?
     
  2. Listed1ST.com macrumors newbie

    Joined:
    Feb 2, 2008
    #2
    1st Step

    I'm not imagining that this will solve you problem, but hopefully it'll start you off on the right track.

    There is a utility to adjust the bandwidth allocation on the Mac Pro

    In system/library/coreservices you will find "Expansion Slot Utility"

    This brings up a window on the Mac Pro to choose which slots get what bandwidth. Dunno if it'll do anything on a MBP.

    Good luck!:apple:
     
  3. xraydoc macrumors demi-god

    xraydoc

    Joined:
    Oct 9, 2005
    Location:
    192.168.1.1
    #3
    How is 3D performance when booted into MacOS X? Is the slow performance a Windows thing or does it also affect MacOS X? If its just Windows, might then be a corrupted driver or something. I'm not an expert at registry diving, so a reinstall (of Windows) may be in your future.
     
  4. LoneWolf121188 thread starter macrumors 6502a

    Joined:
    Jun 7, 2007
    Location:
    Longmont, CO
    #4
    I don't have any Mac programs that are particularly graphics intensive, so I don't really know. What I do know is that if I go into System Profiler, I see 1x under PCI Express Link Width instead of 16x, so I assume that my 3D performance in OS X is also poor.

    I tried running it and I got an error: "Expansion Slot Utility is not intended to run on this system." Thanks though.
     

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