M6800 Heatsink mod idea... awaiting feedback.

Discussion in 'Hardware Components and Aftermarket Upgrades' started by derei, Jan 12, 2018.

  1. Khenglish

    Khenglish Notebook Evangelist

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    Don't put two radiators in series. The misalignment in the fins will cripple air flow. Try to find a little bit thicker one and replace the existing radiator.

    You can also make radiators denser. For how thin yours is you can disassemble your radiator and sand the fin edges down, then reassemble at around 50% higher density. You need to have a 2nd radiator to also break down to maintain the length. When I did this I got a 6C improvement, and I think you'd get even more. You will need to dust your laptop more often, which is why I think the rads aren't made thicker to begin with.
     
  2. Danishblunt

    Danishblunt Notebook Virtuoso

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    As stated heatpipes are not really your issue right now, it's the heatsink size. You need more fins and mass and possibly a better fan.

    Sidenote on what kenglish said:
    You can add more fins, but don't add to many since you will worsen your airflow and make it worse. So make sure you still get a decent airflow.
     
  3. derei

    derei Notebook Consultant

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    Yes, that is the reason why I started to document myself about improving it. I replaced my video card from FirePro to 980M which made a huge difference. That was the first time when i opened this machine.
    Funny thing, this machine is heavy like hell (4kgs) and thick (~3.5cm), still the cooling is designed to allow too little.

    Thank you for the video! Extremely instructive. And for the oven tip.
     
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  4. derei

    derei Notebook Consultant

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  5. Danishblunt

    Danishblunt Notebook Virtuoso

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    Liquid ones are much better so you can spread everything properly.

    https://www.ebay.com/itm/100g-Solde...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

    I used this for custom heatsinks.
     
  6. derei

    derei Notebook Consultant

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    I totally agree with you especially when soldering flat surfaces. I wrote to them asking if they provide those as paste... we'll see.
    Do you know anything about thermal conductivity of this paste? Whilst it should have a very thin layer only (hopefully, if anything goes on right), still a low thermal conductivity so close to the CPU could have negative effects.

    Edit: nvm... found the thermal conductivity of that one: 19W/mK (http://alasir.com/reference/solder_alloys/)
    screenshot here: https://imgur.com/ztppE9i
     
    Last edited: Jan 13, 2018
  7. Danishblunt

    Danishblunt Notebook Virtuoso

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    It's solder, it's high enough for you to be satisfied. As I said, your focus really shouldn't be on conductivity right now. As me and kenglish already told you it's way more about your heatsink and fans. You need to make it bigger, add more fins, add a different fan into your case etc. Even if you were to replace your heatpipes with 3x thicker ones, you'd have next to no impact on temps, since the bottleneck is entirely on your fan / heatsink.
     
  8. darnok44

    darnok44 Notebook Consultant

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    Hi
    I do agree that solder is't Your problem, it's so thin layer of it that it not affect conductivity much. Besides it's used for joining heat sinks with heat pipes and radiators in factories for a reason, because it's the best solution. Much, much more gains can be achieved by focusing on radiators and fans. It simple, more air fan moves it's better. Finding fan with higher CFM and replacing old one is good direction.About radiator, I don't know if You look actually on it but it is different from type which, I think Khenglish, was modding. The heat pipe is soldered directly on top of it. That's why making it denser isn't option. There's really no way to keep those separate fins together during soldering, or at least it would be extremely difficult.
    That's, what I think, looks like cross section of the radiator: But derei have heat sink "in his hands" and can confirm or show us how it really looks like.

    cross section.png
    Replacing radiator part with copper one would help for sure as well but it's matter of finding one. There are some DIY copper heatsinks on the Aliexpress but they would need to be modded off course to fit them into the chassis on the place of aluminium one.
    But I don't agree about conductivity. I don't know on base of what You draw Your conclusion that more heatpipes or bigger one would not improve temps. If I look on the heatsink itself, immediately what stands out is that for a look of it , closer radiator on the right is connected to the cpu plate with narrower heatpipe. It doesn't make sens for me. Why, judging by the eye, radiator with two times more surface area is connected with smaller heatpipe? I would look into this area. It would took quick test to see if extra heatpipe would help there. Take out motherboard from chassis and check under load what are the cpu temps. After that source some short flat heatpipe, either from desoldering old laptop heatsink or buy new one and put on the top of heatsink or even stack it on the existing heatpipe connecting cpu plate with actual radiator. Use maybe very thin thermal tape or thermal paste to allow better heat transfer and repeat stress test. That could give You some insides if the limits of current configuration are actually there. It's not the best and accurate way but quite easy to do. Anyway that were my two cents, maybe will be helpful.
     
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  9. derei

    derei Notebook Consultant

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    @darnok44 thanks for your input. Soon the new heatsink assembly will arrive (I ordered a spare one, as I don't want to risk damaging my existing one and have my laptop non functional). Once I have it in hands I can work on it and see what can be done.
    First steps will be to do some thermal transfer tests, so I can have some results. Then I will also look into your idea of getting more contact surface between radiator fins and heatpipe. Indeed, at the moment it's only connected at the bottom, so the contact area is rather small. Your suggestion is interesting, but it depends on how much I can modify. And of course, I want the modifications to be within a limit, so it would be practical to others to follow it if they wish so. If I redesign the heatsink (almost) entirely, then it may be too discouraging for others.
     
  10. darnok44

    darnok44 Notebook Consultant

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    Actually my main idea was to check if this smaller shorter heatpipe isn't a bottleneck in this heatsink. And if this would be the case, add second heatpipe above existing one, which not only possibly help cool cpu die but as swell VRM's and chokes which are above cpu and covered with the heatsink to. I didn't think about that in that way that it will increase contact area between heatpipes and radiator but when You bring that up...yes, adding second heatpipe would do that also.
     
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