XPS 15 9550 temperature observations (undervolt + repaste)

Discussion in 'Dell XPS and Studio XPS' started by custom90gt, Dec 28, 2015.

  1. custom90gt

    custom90gt Dellerator Moderator

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    Are you asking if the PCH temp is the southbridge? If so yes. It's the bare chip somewhat near the battery connector.
     
  2. Cooler-master

    Cooler-master Notebook Enthusiast

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    Thanks. I padded southbbridge, but the temperature Intel PCH did not go down. That why i asked about this temp.
     
  3. custom90gt

    custom90gt Dellerator Moderator

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    I think it's somewhat difficult to cool because of the distance. Do you have other things sinked to the bottom of your cover? Sometimes that can overwhelm it so to speak.
     
  4. Cooler-master

    Cooler-master Notebook Enthusiast

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    Ssd have stock pad. Vrm pads and chokes.
    After 15 min of end of burn test in Prime 95 temp goes down(cpu 35, vrm 41, ssd 39). Botton is warm, not hot. But PCH temp still at 61-62. And the fan is 3200 rpm. After 1 hour working with notebook the temp of PCH goes down to 42, and the fan is 0 rpm.
    Maybe Intel PCH is not south brige?
    I check - the south bridge have a good contact with cover.
     
  5. custom90gt

    custom90gt Dellerator Moderator

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    I mean it should be the PCH. @pressing , do you want to comment here. I sinked mine but never looked at PCH before/after temps.
     
  6. _sem_

    _sem_ Notebook Evangelist

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    Maybe the pad isn't touching the case? I've padded mine with TG 8 pads but it is still warm (over 50) when on the WD15 dock. Maybe try copper plates with just thin pads for seating (mind fixing well with isolating tape).
     
  7. Cooler-master

    Cooler-master Notebook Enthusiast

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    The contact is very good. I look it when i open the cover.
    When i look on battery youtube 1080p the PCH temp near 40-45.
    BUT! In idle on battery 32-36, when i plug AC charge the temperature rise to 42-45 and then the fan is turns on at 2600 rpm. Why? Notebook is on idle. CPU, VRM, SSD is 30-35 at AC plug in idle.
     
  8. _sem_

    _sem_ Notebook Evangelist

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    The fan seems to be trriggered at these relatively low PCH temps. And that the fan doesn't cool the PCH at all ;)

    Considering that we have no influence over fan thresholds and that Dell obviously doesn't care, you could only try a better heatsink. Even with good contact, thick pads aren't best there is, Cu or Al is much more conductive. And replacing the black insulation with a thin pad might help.
     
  9. Cooler-master

    Cooler-master Notebook Enthusiast

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    Why the temp of PCH is rising when i plug AC? CPU freq is still 800 mhz.

    Thermal pad at south bridge does not have influence on PCH temp. But the cover is warm in a part of a cover, where the padding south bridge is located. It means thermal contact is good.
    I use 5mm thermal pad. It is impossible to use copper pad.
     
  10. _sem_

    _sem_ Notebook Evangelist

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    Dunno why, maybe works more (on battery many things are restricted), maybe it gets heated by nearby power supply components. Mind there is no airflow there. With the WD15 dock (power + external QHD display), the PCH temperature is even ca 10 degC higher than with the AC charger.

    Sure it is possible to use a sandwich like 4mm copper + .5mm pad on both sides, fixed with insulation tape at sides, but dunno if it would help (not if the case feels warm there as you write). Maybe it would be possible to thermally "sink" the PCH to the nearby vent case which is expected to be cool with a copper strip (mind proper wrapping and fixing with insulating tape). But there might be other temperature sensors triggering the fans...
     
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