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laptop GPU overheating- question about copper shim plates installed between GPU and heat sync

Hi I purchased a cheap laptop on ebay, it was an HP DV9000 series. I know they have a common problem where they overheat but I have had good luck with them and I got it for a very low price so I decided to buy it. The seller also noted it had a copper heat sync shim installed to keep it running cooler. The laptop was delivered and I inspected the circuit board and I found that it was not 1 single shim installed but two shims were installed one on top of the other, with heat sync compound in between the two copper shims.

Each copper shim is 0.55 mm thick (1.10 mm with both of them on top of eachother).

My question is would it be better to install these copper shims back (using a good heat sync paste) and should I put the paste in the middle of the two copper shims like it was when I purchased it? Or should I order 1 thicker copper shim (1.1 mm thick)?  In other words what is the proper way to do it?
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hydrive1902
Asked:
hydrive1902
3 Solutions
 
stevepcguyCommented:
The proper thing to do would be to contact your seller... two heat sinks? That doesn't sound like you bought something as described. At the very least, I wouldn't buy from that seller again.

That being said, the most efficient heat sink would be the single 1.10 mm shim.
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CompProbSolvCommented:
Is the shim the same size as the CPU face that it contacts or is it significantly larger?  If it is the same size, I would think that NO shim would be preferable unless the system was designed for the presence of the shim to get the spacing correct.  If the shim is larger, the parts that exceed the CPU face will conduct some heat away to the air inside the laptop.

The goal is to get good thermal conductivity between the CPU and whatever is pulling the heat away (the heat dissipater). A very thin layer of heat sink compound should be used because the two surfaces are not perfectly flat.

One could argue that the softness of the copper aids in thermal conductivity by contouring to the non-flatness of the other two surfaces, but then the heat sink compound should not be used with the copper.

If a shim must be used, one of the proper thickness would be preferable to two thinner ones because they would not make perfect thermal contact with each other.
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nobusCommented:
i have repaired quite a few of them  - and i found the shims are NOT needed
some people think the heatsink does not contact the GPU properly - but i did never notice that.
What was needed in many cases, was to reflow the GPU
you can find many topics on the net, and Youtubes on how to do it : in an oven, with a heat gun (i used this method) and it does work well. (up to now)

adding copper shims always adds in this case 3 resistor layers for the heat GPU->shim1->HP-->shim2-->HP-->cooler sink (HP= heat paste) - even if the resistances are low
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hydrive1902Author Commented:
Thanks for the info. I decided to not install the copper shim I just used some good thermal paste and I have ran the laptop for 12 + hours and it is still running fine and shows no signs of overheating.

The shim was larger then the GPU but it does look like the seller tried to take a short cut by using 2 shims rather then using the right thickness one. But it is ok because it appears no shim is needed, as nobus mentioned.

Also I got it very cheap, so I cant complain too much because I got it for $80 (USD)  and that includes shipping. It also came with an extra working LCD. Just the LCD alone sells for $50 (17" LCD). I know that because I had to replace my original a few months ago (I use the same model computer - dv9000 series for my own personal computer).

thanks for the info everyon!
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nobusCommented:
tx for feedback
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