Thermal paste on laptop CPU/GPUs (avoiding pumpouts)

Discussion in 'Hardware Components and Aftermarket Upgrades' started by SJLPHI, Aug 6, 2020.

  1. SJLPHI

    SJLPHI Notebook Consultant

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    https://www.keyence.com/ss/products/measure-sys/gd-and-t/form-tolerance/flatness.jsp

    If you see the Lenovo T480 heat sink, you'll notice that overpressure is more likely than underpressure. It's just designed badly.
     
  2. custom90gt

    custom90gt Doc Mod Super Moderator

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  3. Papusan

    Papusan JOKEBOOKs Sucks! Dont waste your $$$ on FILTHY

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  4. SJLPHI

    SJLPHI Notebook Consultant

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    A confocal laser CMM

    Have you tested a modern Lenovo? Their obsessions over thinness comes at great costs. Ranging from keyboards touching the screen when the lid is closed, and inadequate thermal solutions.
     
    Last edited by a moderator: Aug 29, 2020
  5. custom90gt

    custom90gt Doc Mod Super Moderator

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    And what was the difference in z-height, and which heatsink were you measuring? Also what about the test mounting? If you have a perfectly flat heatsink with good pressure, you shouldn't have pump out with any thermal paste. Also I'd love to see pictures of your CMM setup, I've owned a lot of laptops and I've yet to see a perfectly flat heatsink.
     
  6. SJLPHI

    SJLPHI Notebook Consultant

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    The heatsink for T480 on a 5mm thick piece of +/-2 micron aluminum all purpose jig vacuuming down points of interest. Flatness measurement is ~+/-68 microns which is more than "flat" enough for a laptop heatsink considering it gets at least a 1mm layer of thermal paste.

    I don't think I have the clearance to publically post a picture of the lab.
     
  7. Papusan

    Papusan JOKEBOOKs Sucks! Dont waste your $$$ on FILTHY

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    I',m not sure what you mean with modern Lenovo. But have benched L460 and E480. The Cpu in the Lenovo E480 with the power gimped i5-8250U perform around or above an 45w H class chips (i7-6700Hq).
    [​IMG]

    And this one haven't the pump out of paste problem as your so called overpressure/perfect machined heatsink. What you think/belive is an perfect machined heatsink is only an illusjon. There is always same reasons for thermal paste pump out.... Bad heatsink fits combined with an soft and creamy thermal paste as Kryonaut.
    upload_2020-8-29_14-23-15.png
     
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  8. SJLPHI

    SJLPHI Notebook Consultant

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    Of course the "points of interest" are the contact points individually, not the whole thermal system including the heatpipes and etc.
     
  9. custom90gt

    custom90gt Doc Mod Super Moderator

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    And these points of interest include the CPU and GPU mounting surface and comparing between the two?
     
  10. senso

    senso Notebook Deity

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    Something is very wrong if you have a 1mm layer of thermal paste...
    And that also explains the pump out, thermal paste is not made to be stable with 1mm thickness..
    Fix your pads and let your heatsink TOUCH the die..
    Thermal paste is there to fill micro irregularities, not macro.
     
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