What is the brown sludge on the ATI chip?

[burns334]

T42 with the long fan, all this stuff is ozzing out around the interface of the fan housing and the chip, I am having the chip reballed by GPUmedics and want to use the "right stuff" when reinstalling the fan.

[poshgeordie]

The 'stuff' you're talking about is bonding material to make sure the heatsink is stuck to the top of the graphics chip.

There's a thick heatsink pad in the middle of the heatsink which transfers the heat from the GPU.

Hopefully GPU Medics will carefully break bond between the heatsink and gpu with a minumum of damage to the GPU. The correct way to do it is to remove the three screws from the heatsink.
Then use a tiny slotted screwdriver against one corner of the heatsink on the GPU, wiith it placed horizontally. Then tap the end of the screwdriver to cause the heatsink to gently lift off the GPU.

When replacing the heatsink it's not necessary to replace the 'stuff'.

Also there's no need to use heatsink compound between the pad and the GPU when replacing the fan.

[burns334]

Nick,

No problem at GPU Medics, I sent them a bare motherboard, lol. It came off the chip with no problem at all. just lifted up.

I'm a little confused about the word "pad" do I need to add something at that interface?
Thanks

[poshgeordie]

There should be a pink coloured pad under the GPU part of the heatsink. This is a thermal pad and is rather like thick heatsink compound. If there's not pad there, you will need to put one on there.

If you need to buy one they are available from eBay. You'll need to cut it to size.

[Ralf Hutter]

There should be a pink coloured pad under the GPU part of the heatsink. This is a thermal pad and is rather like thick heatsink compound.

Can you just use Arctic Silver, or some other type of thermal paste instead of using one of those pads?

[Harryc]

The problem with not using a pad is you may not make proper contact between the GPU heatsink and the GPU. The thermal pad is 1 to 2 mm thick, so that's a ton of Arctic silver needed to cover the gap, and Arctic Silver is designed to work best using a paper thin layer. If you try to bend the GPU heatsink down you throw off the entire geometry of it and will probably make the situation worse.