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    XPS 1645 - Hotter when AC plugged in

    Discussion in 'Dell XPS and Studio XPS' started by mertkizilay, Jan 10, 2011.

  1. mertkizilay

    mertkizilay Notebook Enthusiast

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    Hello all,

    Not a big issue, but i m just curious; when this laptop on battery, no matter which power plan is set, slightly cool and silent. But when i plug ac in, (90W or 130W doesnt make difference) it runs hotter. It s not necessary what i m doin, browsing on internet or just desktop, fan is running almost all the time unlike on battery.

    Do you know anything about this?
     
    mertkizilay, Jan 10, 2011
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  2. JKleiss

    JKleiss Notebook Evangelist

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    It is most likely throttling when on battery.
    The BIOS will be not allowing the cpu/gpu to draw as much power as they want so they will be downclocked.
     
    JKleiss, Jan 10, 2011
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  3. mertkizilay

    mertkizilay Notebook Enthusiast

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    Strange, throttling is an issue, however it s more reasonible to work cool and silent when doin simple tasks. But this related to throttling then
     
    mertkizilay, Jan 10, 2011
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  4. gpig

    gpig Notebook Deity

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    There's a few things going on-
    1. The power plans have different settings for Plugged-In and Battery. Especially take a look at "ATI Powerplay" which usually defaults to "maximum battery life" on battery and "maximum performance" when plugged in.

    2. However even if you customize the power plans to be the same on battery as plugged in- the battery can only draw around 90w for an extended amount of time (can draw higher for a short amount of time- mine hit 97w), so the 130 watt adapter should run hotter in cases where a lot of power is being used (probably only videogames or benchmarking). You're probably not maxing out the AC adapter which would explain no difference between 90w and 130w adapter.

    3. Many background services (mostly 3rd party programs) disable themselves temporally when on battery. This could potentially be a difference maker.

    4. Are you comparing the heat difference when the laptop is charging the battery? This will also make a difference.
     
    gpig, Jan 10, 2011
    #4