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Thread: About the thermal paste

  1. #1

    Question About the thermal paste

    I have an old laptop. I suspect the thermal paste has gone dry or bad. But I don't want to disassemble the laptop, because it is quite a work. There is no issue of dust inside the laptop.

    I am wondering whether it is possible to learn about the state of the paste from CPU's load-temperature curve. I obtained the temperatures from KSysGuard which uses hardware sensors. The laptop is running on external power.

    The processor's T_junction (maximal temperature) is 100 C according to Intel.

    What bothers me is that the fan rotates most of the time already at 68 C. There is little load on videocard.

    Here is what I got:

    Load, % Temperature, C Fan rotates? Frequency,
    % of max
    20 44 No 100
    25 49 No 100
    45 57 Sometimes 100
    60 60 Mostly 100
    70 68 Mostly 100
    82 68 Always 100
    100 71 Always 100

  2. #2
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    Default Re: About the thermal paste

    Hi
    What can happen is a dust wad in the cooling fins at the end of the heat pipe... shine a light on the bottom of the laptop where the fan entry is and look into the exhaust point on the laptop, can you see light through each of the fins (you might need to move the light source around)?

    What GPU is in the laptop? If AMD and using radeon driver, try setting the power profile to low.

    Else disassemble (look on youtube for your model and disassembly) and remove the old (I'm expecting wax thermal compound) compound with a cotton bud and isopropyl alcohol and replace with something like artic silver (they have good instructions on what to do)...
    Cheers Malcolm °¿° SUSE Knowledge Partner (Linux Counter #276890)
    SUSE SLE, openSUSE Leap/Tumbleweed (x86_64) | GNOME DE
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  3. #3

    Default Re: About the thermal paste

    Definitely there is no dust.

    I am trying to avoid disassembly if the paste is good... It is 1/2 days of work.

    The graphic card is NVIDIA GeForce 8400M GS. The nouveau driver drives it.

  4. #4
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    Default Re: About the thermal paste

    Quote Originally Posted by ZStefan View Post
    Definitely there is no dust.

    I am trying to avoid disassembly if the paste is good... It is 1/2 days of work.

    The graphic card is NVIDIA GeForce 8400M GS. The nouveau driver drives it.
    Hi
    So does the nouveau driver show in the sensors output for temperature? No separate fan for the GPU I would assume...

    How old is the laptop?
    Cheers Malcolm °¿° SUSE Knowledge Partner (Linux Counter #276890)
    SUSE SLE, openSUSE Leap/Tumbleweed (x86_64) | GNOME DE
    If you find this post helpful and are logged into the web interface,
    please show your appreciation and click on the star below... Thanks!

  5. #5
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    Default Re: About the thermal paste

    Quote Originally Posted by ZStefan View Post
    What bothers me is that the fan rotates most of the time already at 68 C. There is little load on videocard.

    Here is what I got:

    Load, % Temperature, C Fan rotates? Frequency,
    % of max
    20 44 No 100
    25 49 No 100
    45 57 Sometimes 100
    60 60 Mostly 100
    70 68 Mostly 100
    82 68 Always 100
    100 71 Always 100
    I don't know how much confidence we should have in those numbers, but a fan triggering about 60 C doesn't look odd to me and if increasing the load from 70 to 100 % really only brings the junction temp from 68 to 71 C I guess the cooling system is still doing a fair job.
    Maybe it is not as good as it was out of the factory, but still working and not needing a replacement of the thermal paste.
    When the junction to heathsink coupling is gone, you can see junction temps going up in a few seconds even with moderate loads; if reaching 71 C from a cold start with 100% loads takes, say, a minute or two, I wouldn't take the hassle of replacing the paste.

    Anyway, it's your machine and so you are the boss...
    Main: Leap 15 Gnome on i7 4720HQ + Geforce GTX960M
    Test: Leap 42.3 (& others) on Core2Duo + GM965

  6. #6
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    Default Re: About the thermal paste

    Quote Originally Posted by OrsoBruno View Post
    I don't know how much confidence we should have in those numbers, but a fan triggering about 60 C doesn't look odd to me and if increasing the load from 70 to 100 % really only brings the junction temp from 68 to 71 C I guess the cooling system is still doing a fair job.
    Maybe it is not as good as it was out of the factory, but still working and not needing a replacement of the thermal paste.
    When the junction to heathsink coupling is gone, you can see junction temps going up in a few seconds even with moderate loads; if reaching 71 C from a cold start with 100% loads takes, say, a minute or two, I wouldn't take the hassle of replacing the paste.

    Anyway, it's your machine and so you are the boss...
    Yep, I agree. The numbers are not bad, at all.

    ... and, about the dust, if the laptop is old -- as you say -- and has been running awhile, you can bet your life savings on it that there is dust in there. There is no way to avoid that, unless ... have you been running it only in a sealed lab on the space station since the day you got it???

    ... or, did you open it up & clean it within the past few weeks?
    -Gerry Makaro
    Fraser-Bell Info Tech
    Solving Tech Mysteries since the Olden Days!
    ~~
    If I helped you, consider clicking the Star at the bottom left of my post.

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