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    Windows 7 RC T400 Battery Life Restored

    Discussion in 'Lenovo' started by BinkNR, May 15, 2009.

  1. BinkNR

    BinkNR Knock off all that evil

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    By default, the BIOS is configured for Switchable Graphics. With the latest video driver updates from Windows Update today, I was no longer able to view my screen consistently (screen blanking/background viewable, but nothing else). I was able to resolve this issue by forcing the BIOS to Integrated Graphics—and the positive side effect of this is my battery life went back to 4-5 hours (from about 2)! I’m quite pleased now—and this actually makes some sense too. Since Windows really doesn’t know how to handle these switchable graphics cards without Lenovo’s drivers, it probably kept both of them on.
     
    BinkNR, May 15, 2009
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  2. Lew

    Lew Notebook Deity

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    Nice catch. Also have to set the second item in the BIOS which causes the BIOS to switch back to switchable if it detects an OS that can handle it.

    Going to give it a shot -- issue for me hasn't so much been batter life as heat generation. I still consider these things as "laptops" and my T400 had been a bit toasty since switching to Win7 RC.
     
    Lew, May 15, 2009
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  3. BinkNR

    BinkNR Knock off all that evil

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    Yea—I forgot to mention that part of the BIOS. Since I made this change, the notebook appears to generate less heat as well.
     
    BinkNR, May 16, 2009
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  4. w500?

    w500? Notebook Consultant

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    Isn't that the point of switchable graphics, to increase battery life over a dedicated card? Or are you saying you were already on integrated and battery went from 2 to 4-5 hours after making the change?
     
    w500?, May 16, 2009
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  5. BinkNR

    BinkNR Knock off all that evil

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    I’m saying the setting was Switchable Graphics—and when I switched it to Integrated Graphics, my battery life went back to normal. I am assuming this is because Lenovo does not support Switchable Graphics under Windows 7 at this time—and both graphics cards were powered on on my system. While the Intel card was being used by Windows 7 for my display, I assume both it and the ATI card had power flowing through them.
     
    BinkNR, May 16, 2009
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  6. Lew

    Lew Notebook Deity

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    Following up -- this change makes a huge difference, seems that Win7 was not properly handling the two GPU's and had both running. Since I locked it to Integrated in the BIOS I'm back to normal.

    Thanks BinkNR!
     
    Lew, May 19, 2009
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  7. BinkNR

    BinkNR Knock off all that evil

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    Glad to hear I was able to help/it works for you too!
     
    BinkNR, May 19, 2009
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