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Gap between heatsink & GPU

Discussion in 'Overclocking & Cooling' started by Kantastic, Feb 27, 2011.

  1. Kantastic

    Kantastic

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    For the past few months I've been using a copper shim between the GPU and heatsink of my laptop because there's a rather large (1mm~) gap between the two. The thing is getting rather hot, to the point where my hand would start numbing after touching the bottom for too long. I can't remember how the laptop was like prior to me taking it apart (for fun) to replace the TIM with MX-2. The laptop originally had a thermal pad between the GPU and heatsink, but that obviously ripped when I dismantled the laptop.

    I assume the gap is far too wide to simply fill up with TIM, but I'm sure there's a better solution than a flat copper shim because the heatsink base & GPU are not parallel, there's a slight slant, so I'm not sure how the contact is. It's also transferring heat between three layers (two layers of TIM and the copper), which has got to be hindering cooling.

    I've been trying to find high-quality thermal pads, but I can't seem to find any on popular tech shops. Maybe I'm just looking for the wrong thing (are they even thermal pads?) or they're just impossible to find.

    SOLUTIONS PLEASE!
  2. Laurijan

    Laurijan

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    One guy at TPU has a ongoing sales thread for thermal tape - i dont remember more...
    Kantastic says thanks.
  3. Loosenut

    Loosenut

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    Thermal tape is too thin, what Kantastic needs is a thermal pad similar to what EK sells.

    I'm sure you can find the same or similar around your neck of the woods Kant
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  4. Kantastic

    Kantastic

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    Definitely not thick enough, the gap is at least 1mm.

    There ya go! Thanks so much! I'm going to give these a shot, I found them in the USA. THANKS AGAIN!
  5. Laurijan

    Laurijan

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    Kantastic says thanks.
  6. Kantastic

    Kantastic

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    I don't know about thermodynamics, but between the finger oils and dust between all the layers, I doubt the performance will be better than my copper shim.
  7. Loosenut

    Loosenut

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    It's what I use for my GPU blocks. Glad I could help :toast:
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  8. scaminatrix

    scaminatrix

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    The copper shim may be too thin.
    I can help with sourcing these copper shims if you need a thicker one.
    A copper shim should perform much better than a thermal pad IMO.
  9. AsRock

    AsRock TPU addict

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    Any chance of some pictures as it's kinda crazy thinking that the manufacture left a 1mm gap but you never know huh.

    maybe it's just not lining u right with some thing ?. And copper is going be way better if you can get 2 of the right thickness.

    Edit: maybe some things to tight or just not lined up right.
    Last edited: Feb 27, 2011
  10. Wimpelmann

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  11. scaminatrix

    scaminatrix

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    I should have given you a proper link, sorry.
    Here's a shop on the bay that sells copper shims specifically for certain laptops. Another member on here wanted one, he had to measure his old thermal pad to get the right thickness (as they didn't have details on his laptop).
    You can measure the gap by placing some blu-tac on the GPU (with a small piece of paper between the blu-tac and HS to stop it sticking to the HS) and fitting the laptop back together, then taking it apart again.
    Then cut away the excess blu-tac from around the the GPU and measure it. For the easily scared, don't worry Blu-tac is surprisingly easy to remove from motherboards.

    It sounds strange, but after having a long hard think of how to measure that gap without a feeler gauge etc., it's all I could come up with :eek:

    Attached Files:

  12. CBRworm

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    A copper shim properly sized should work very well. It seems unlikely that there was that significant of a gap from the factory. Is is possible something was re-assembled improperly? There should be no gap for paste TIM and only a few thousandths of an inch for a pad unless it is an unusually thick pad. 1mm seems way too big of a gap.
  13. overclocking101

    overclocking101

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    no matter a thermal pad or not if you have a gap its gonna have shitty heat transfer, my suggestion is working on a preassure mod of some sort to makre your gap go bye bye. copper shims are the best for gaps thermal pads will not do anything but make it worse. think of it like this. vrms use thermal pads but when all vrms arent getting proper contact they over heat, and compared to a cpu vrms dont get nearly as hot as fast. what do we do when our vrms arent getting contact?? add a backplate or some washers on the screws. thats my suggestion. maybe take pics if im getting you wrong.
  14. CBRworm

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    What he said. . .
  15. Kantastic

    Kantastic

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    I checked my eBay purchase and it turns out the shim I bought was .56mm thick, I thought it was .75mm thick. The gap is roughly 1mm, I would say anywhere from .75-1mm, I'm going to double check again when I have the chance.

    That's just how HP/Compaq laptops are, the main market for copper shims is HP laptop owners. Apparently large gaps & poor conducting thermal pads is a notorious issue.

    I'm almost positive there was no issue with reassembly since I did it like 4 times.

    I was afraid thermal pads wouldn't work as well as TIM and a piece of copper.

    I honestly don't know why there's such a large gap between the heatsink and GPU. Any sort of mod is out of the option because the GPU & CPU heatsink is one piece connected via a copper heatpipe. The heatsink for my particular laptop (Compaq CQ60-220US) also has no screws for the GPU block, it relies solely on the pressure from the 4 screws on the CPU block. Not only is a pressure mod out of the question, even if it were possible I'd probably ruin the contact on the CPU end or even worse, break something.

    The only thicknesses I can find on eBay are .56mm, .66mm, .8mm, 1mm, 1.2mm, and 1.5mm. I don't want to wait 2 weeks for the shim to come from Asia, so the only options left from US sellers are .56mm, .66mm, and 1mm. I just ordered a 1mm piece, hopefully a thicker piece will make tighter contact and result in better heat conduction.

    I'm also giving the EK thermal pad a shot too. Next step is to figure out how to monitor my CPU/GPU temperatures to see which is the better option.
  16. Jstn7477

    Jstn7477

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    Have you tried HWMonitor from the people that make CPU-Z? Works good with both my new and old laptops (although there doesn't seem to be a temperature sensor in my RS880M to read, but my CPU, NB and GPU are all on the same heatpipe so it doesn't matter too much).
    Crunching for Team TPU More than 25k PPD
  17. Kantastic

    Kantastic

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    I see two temperatures (TZS0 & TZS1) but the CPU cores are stuck at 84/83. I'm not sure what the TZS values are, but they're fluctuating a bit.
  18. Jstn7477

    Jstn7477

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    Interesting. Well, good luck with your mod. I had an old HP DV6000 back in the day that had one of those stupid thermal pads, but it was just a crappy Turion 64 X2 TL-50 and GeForce 6150 IGP so I didn't care about it. There might be one on my northbridge (I can't remember), but again the HD 4250 runs cool enough, and my 5650 + CPU have direct contact on the same heatpipe and maintain temperatures of 70c or less under load, so all is good. :toast:
    Crunching for Team TPU More than 25k PPD
  19. AsRock

    AsRock TPU addict

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    Think your on to some thing there, maybe soft rubber washers to get it some what flat with a copper plate maybe.

    Eww thank god i did not pick one of those up lol. I guess i can be happier mines a DELL and uses screws.
  20. overclocking101

    overclocking101

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    can you bend the heatpipe just a bit?? I had to fix a laptop that way, no screws on the gpu and it was so bad it wouldnt boot windows before shutting down. used needle nosed pliers and some patience to get it right but you can bend the heatpipe to force more gpu preassure
  21. Kantastic

    Kantastic

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    The heatpipe is soldered onto a solid piece of metal, no clue what type but I tried bending it and it wouldn't budge. I'm thinking a shim is my only option so far.

    Would anyone happen to excel at thermodynamics and know whether or not a large shim would work better than a smaller shim with the same thickness?

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