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    Penryn minimum core temperature?

    Discussion in 'Dell' started by manekineko, Jul 13, 2009.

  1. manekineko

    manekineko Notebook Geek

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    It seems like the temperature readings from both cores of my P8400 on my Dell Latitude E6500 running Windows 7 RC have some sort of minimum built into them. The reported temperatures will never drop below 32 for Core 0, and 39 for Core 1. Even after I resume from suspend, when the CPU should be at room temperature, as soon as I boot up it's 39/32. Similarly, while temperatures above that on SpeedFan show normal fluctuations, like you expect from a CPU temperature reading, once it hits the floor, it just becomes a flat straight line.

    I'm not sure if this is the sensors, the software, or what.

    Anyone else see this on their computers? Is it a Penryn thing, a Dell thing, etc?
     
    manekineko, Jul 13, 2009
    #1
  2. Mastershroom

    Mastershroom wat

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    I haven't checked per core, but I've never seen my Penryn T9500 below 29C.
     
    Mastershroom, Jul 13, 2009
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  3. namaiki

    namaiki "basically rocks" Super Moderator

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    I've seen my P8600 at 16C, but not for long... t'was a very cold night.

    But right now it's 44C.
     
    namaiki, Jul 13, 2009
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  4. Fragilexx

    Fragilexx Get'cha head in the game

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    On my Dell with a Penryn core I have seen no such floor built in. I have seen my processor drop down to about 20 degrees Celsius when starting from standby or somesuch, and it idles at just under 30. I don't think it's anything to worry about though; as long as it's reading the right temperature at the upper end of the scale - that's what the sensors are for.
     
    Fragilexx, Jul 13, 2009
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  5. manekineko

    manekineko Notebook Geek

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    Bizarre, I wonder what's special about my setup that is causing this. Even when I boot into Ubuntu, I'm encountering the same phenomena, only there the two numbers for the floor are 27 and 34 (exact same spread, probably a different formula being applied to calculate the temperature).

    Even an air conditioner blowing directly on the computer, which feels to the touch colder than room temperature, has no effect on the reported temperature.

    In Windows I was using Speedfan and Coretemp. What are you guys using to monitor the temperatures?
     
    manekineko, Jul 13, 2009
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  6. namaiki

    namaiki "basically rocks" Super Moderator

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    HWMonitor from cpuid.com
     
    namaiki, Jul 13, 2009
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  7. manekineko

    manekineko Notebook Geek

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    Tried HWMonitor, it reports the same 27/34 numbers as Ubuntu. All of HWMonitor, SpeedFan, CoreTemp, and Ubuntu all show this puzzling minimum temperature phenomena.
     
    manekineko, Jul 13, 2009
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  8. manekineko

    manekineko Notebook Geek

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    manekineko, Jul 13, 2009
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  9. mullenbooger

    mullenbooger Former New York Giant

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    My penryn (non-dell) has definitely gone lower, but generally only in the winter when its sleeping. It'll quickly ramp up though once its in use.
     
    mullenbooger, Jul 14, 2009
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  10. manekineko

    manekineko Notebook Geek

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    Just in case anyone else is in the situation, I have confirmed that this was due to defective sensors in the CPU, which are common in Penryn (45nm) CPUs. Dell swapped out my CPU, and now everything is working as expected.

    Additionally, I had previously been seeing some weird readings on the high side, which probably were a pretty bad sign, where at full load one core would read temperatures 20-30 degrees higher than the other. That has also disappeared after the CPU was replaced.
     
    manekineko, Jul 15, 2009
    #10