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    Switchable graphics on the T400

    Discussion in 'Lenovo' started by zhaos, Jan 11, 2011.

  1. zhaos

    zhaos Notebook Consultant

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    What is the situation today with regard to switchable graphics for the T400 on Windows 7? I am running vista, and I am wondering if the issue of both ATI and intel graphics coming online after resuming from standby still exists on windows 7.
     
    zhaos, Jan 11, 2011
    #1
  2. vinuneuro

    vinuneuro Notebook Virtuoso

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    It's fixed with the latest graphics driver update.
     
    vinuneuro, Jan 11, 2011
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  3. vimvq1987

    vimvq1987 Notebook Consultant

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    latest driver fixed power issue, but causes a number of annoying bugs with Intel driver
     
    vimvq1987, Jan 12, 2011
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  4. MidnightSun

    MidnightSun Emodicon

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    The issue is now fixed, and switchable graphics should work properly either with the latest switchable graphics drivers from Lenovo or the latest appropriate driver package from AMD (the latter may result in an inability to adjust screen brightness while on discrete graphics mode).

    What bugs would those be? So far, I don't think I've had any problems. Certainly far better than when I had to toggle the graphics sets to turn off the discrete graphics after standby, at any rate.
     
    MidnightSun, Jan 12, 2011
    #4
  5. vinuneuro

    vinuneuro Notebook Virtuoso

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    The only annoying bug I've found is that the Intel driver automatically changes the refresh rate to 50hz on battery without giving an option to change this behavior. I think this was there in the previous version to,o and it's not specific to this chipset since T410 users experience it too.

    The simple fix is to disable igfxpers.exe from starting up, but I'm going to see if the lower refresh rate bothers me at all when doing reading/writing type work. Might as well take the extra battery life that comes with it if it doesn't.

    One thing I really wish Lenovo implemented was automatic graphics device switching based on power source. The Ati driver has this feature.
     
    vinuneuro, Jan 12, 2011
    #5
  6. vimvq1987

    vimvq1987 Notebook Consultant

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    please read here for more details

    R400/T400/T500/W500: Switchable graphics - NEW iss... - Lenovo Community

    with AMD driver, it would be not able to change brightness on discrete card mode
    with Lenovo driver, it's usually app crashes. for me, windows help collapses most of times I open a .chm file, and some other crashes. really annoying ...
     
    vimvq1987, Jan 12, 2011
    #6
  7. User Retired 2

    User Retired 2 Notebook Nobel Laureate NBR Reviewer

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    The switching ATI driver just disabled the ATI card, which then defaults to the IGP on the newer series-5 chipsets. If the T400 does the same then it's possible to write a vbscript solution to do the switching by using devcon to disable/enable the ATI card when switching from AC<->DC.
     
    User Retired 2, Jan 12, 2011
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  8. vimvq1987

    vimvq1987 Notebook Consultant

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    vimvq1987, Jan 14, 2011
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  9. ed22

    ed22 Notebook Consultant

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    The problem with the new switchable graphics driver (v 8.752) is that it seems to conflict with Windows Update KB2028560 (installed when you install IE9), KB2454826. This results in crashes in some GDI apps like Outlook and also GPU accelerated browsers (IE9 and Firefox 4). A forum member reported that when he uninstalled both updates, the issues went away.
     
    ed22, Jan 14, 2011
    #9