DIY Thermal Pad Substitute

jbseven

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So I was disassembling my hd 5850 to clean out the dust. My brother saw one of the thermal pads, thought it was some kind of paper/crap I hadn't noticed, and tried to take it off. This was the type that crumbles.

Now I don't have any dead laptops/gfx cards with usable thermal pads, and getting one to my location would take at least half a month.

Are there any diy options I can try?
 

jbseven

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you're absolutely right.

the other thermal pads here look about 1.5mm thick. i would not want to use a viscous layer of TIM here. apart from the insulating factor, i imagine that it wouldn't hold up too well either when the card is vertical.

The chip at the bottom right area between the two screw mounting holes is where the pad was.


 

jbseven

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not really when it crumbles to powder. it also doesn't help half of the other chip which is not a very nice compromise.

there is a nice strip of this crumbly pad on the other side that appears to be unused, but since it would have to be moulded (widened) to fit the chip properly...

also, i'm not familiar enough with pads to understand why half the board uses crumbly pads and the other half uses reshape-able pads. im positive that it either has some function or that it is cost related. anyone?
 


That chip looks like it's part of a VRM (i.e. Voltage Regulation Module) circuit and would put out some heat which needs to be removed.
 


The thermal conductivity is different for each of the different types of pads.
 

jbseven

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here is the whole card surface and the heatsink surface it attaches to. the pad goes on the chip at the bottom right of the card image, and the top right of the heatsink image.





Since the vram uses the malleable pads, i'm guessing the brittle ones aren't as conductive.
 
The pink colored ones are for the memory modules and the white/light gray ones are used for the VRM's FETs.

The gap that needs to be filled and the amount/rate of heat that needs to be removed determines the required conductivity and thickness of the thermal pad.
 

jbseven

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so not even this can be used?
 


If it's the correct thickness you can always use thermal pads that have better conductivity than the original thermal pads.

Just don't use thermal pads with poorer conductivity than the original thermal pads because that's just asking for trouble.