T43 ATI GPU Heatsink Question

[scr71822]

I am wondering if removing the rubber from the Heatsink portion that covers the GPU would be a good idea. It would seem that it would help cooling, however I am concerned about shorting it out by having copper directly on the aluminum GPU cover. Any thoughts?

[ajkula66]

Nothing will short out, no current is being transferred between the two...

My choice is to leave the funky stuff on the heatsink, although I'm certain it would work without it.

My $0.02 only...

[Norway Pad]

Unless there is something here I don't get, I would say that removing the heat transfer pad and leave a gap of air between the GPU cover and the heat sink would drastically reduce the cooling from the heat sink. This pad is meant for actually transferring heat.

And even if you manage to bend and adjust the heat sink GPU plate, so that it makes perfect contact with the GPU cover, you would still need to use heat transfer compound, like it's used on the CPU. Otherwise I would say the the cooling effect from the heat sink would be reduced.

[lukee]

Better solution than gap of air is to swap the "rubber" with same-sized piece of copper and use some high quality compound on both sides.

[goofyGAguy]

Better solution than gap of air is to swap the "rubber" with same-sized piece of copper and use some high quality compound on both sides.

Would a pre-1982 penny be about the right thickness for the job?

[lukee]

to goofyGAguy: Well, I'm based in Europe and paying with Czech crowns, so I don't know. But I think a raw copper would be better because it usually has flat and very smooth sides - it's good for a better heat conduction.

[poshgeordie]

It has to be flat copper of the right thickness. Also use very thin layers of heatsink compound on both sides of the copper.

Things like coins etc won't work because they're full of indentations, and filling the indentations with heatsink compound won't work either becaus the compound is only there to fill in micro scratches / imperfections between the metal surfaces not big "cavities".

[lukee]

I've question about heatsink compound - does it works also as glue or not? If not, it's neccessary to ensure montage of this small piece of copper somewhere in the chassis to protect T43's electronics against circuit short, right?

EDIT: goofyGAguy, could you measure thickness of the rubber with a caliper and share it here, so I can also order copper part without my T43 disassembly Thanks.

[poshgeordie]

I've question about heatsink compound - does it works also as glue or not? If not, it's neccessary to ensure montage of this small piece of copper somewhere in the chassis to protect T43's electronics against circuit short, right?

It works best if it's spread very thinly and will cause the shim to stay in place by "surface tension" (I guess is the best way to describe it).
You do have a point though, and you could apply a couple of spots of superglue at the corners between the shim and GPU heatsink - having applied the heatsink compound first and pressed the shim down on the GP.

We use shims all the time on Nvidia chipped laptops such as HP's and they stay in place with just the heatsink compound, but we prevent any potential shorts onto the top components on those GPU's with Kapton (high temperature) tape.