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Applying Thermal Compound to GPU

nheather

nheather

nheather

Associate
Joined
19 May 2004
Posts
1,037
Location
Horsham, West Sussex
Is the best method to apply Thermal Compound to GPU like that for CPU - apply a blob in the centre and press down.

I ask because

(i) The CPU method doesn't cover the whole area but does do the important bit in the middle where the cores are. Is that okay for the GPU.

(ii) The CPU method involves twisting the heatsink back and forth to help spread the TIM out. But the GPU HSF has 4 mounting lugs that go through the CPU so you can't twist it

I'm using MS-3

Cheers,

Nigel
 
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One rice grain sized drop in the middle should do. When the cooler goes back on it will spread equally in each direction.

You don't need to twist it about.
 
Personally I've always done the technique of putting cling film around your finger and spreading it evenly over the surface.
 
One rice grain sized drop in the middle should do. When the cooler goes back on it will spread equally in each direction.
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This tends to put a circle in the centre of the area - so doesn't go out to the corners and edges.

Fine for a CPU but is this okay for a GPU.

Cheers,

Nigel
 
In the past I have always spread the stuff around using an old fashioned razer blade - ends up quite thin and even.

That has been with AS-5. Just tried it today with MX-3 and that doesn't spread around well at all. Tends to stick to itself, causing clumping rather than threading thinly or clumping onto the blade. I guess the blob and pressure it certainly better for MX-3.

Cheers,

Nigel
 
nheather said:
In the past I have always spread the stuff around using an old fashioned razer blade - ends up quite thin and even.

That has been with AS-5. Just tried it today with MX-3 and that doesn't spread around well at all. Tends to stick to itself, causing clumping rather than threading thinly or clumping onto the blade. I guess the blob and pressure it certainly better for MX-3.

Cheers,

Nigel
Click to expand...

I think I had some of that stuff, read some rave review, How can it be much good ? It's like a lump of playdoe and it does not seem to stick to anything

AS5
small rice grain spot spread across the die then the residue on the credit card wiped across the heatsink at 90 deg to the finishing marks, finished off by a speck in the center of the die
 
Stickiness isn't everything.

It's flattened into a very thin smear between the plates, requires very little adhesion in that situation a thick enough consistency would retain it.
 
I'd certainly apply a thin coat to a GPU with an exposed die, i.e. no IHS. Uncoated corners would be a no no.
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That's what I was thinking. A CPU is different because it (most) have a heatspreader already so what you see is a lot lot bigger than the die.

But for the GPU you basically see the die istelf I think - well it's more of a chip rather than a dirty great lump of metal.

Cheers,

Nigel
 
Hotwired said:
Stickiness isn't everything.

It's flattened into a very thin smear between the plates, requires very little adhesion in that situation a thick enough consistency would retain it.
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No, but for Me I like to control where it goes when it's squished ! Rarely can the Heatsink be lowered down accurately, so you always risk squishing it out one side

Regarding "thick enough consistency" If the surfaces were perfect You would not need any compound, it is there to fill imperfections.
 
nheather said:
That's what I was thinking. A CPU is different because it (most) have a heatspreader already so what you see is a lot lot bigger than the die.

But for the GPU you basically see the die istelf I think - well it's more of a chip rather than a dirty great lump of metal.

Cheers,

Nigel
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No, same deal, the IC potted inside that block (die) and the Block carries external connections and acts as a heatsink
 
nheather said:
That's what I was thinking. A CPU is different because it (most) have a heatspreader already so what you see is a lot lot bigger than the die.

But for the GPU you basically see the die istelf I think - well it's more of a chip rather than a dirty great lump of metal.

Cheers,

Nigel
Click to expand...

Also the exposed versions you have a lot less surface area for heat transfer. Some of the Nvidia cards have the IHS, probably not as important to get right to the edges on those.

G80 IHS removed.
 
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Hotwired said:
What does that have to do with a thick consistency being sufficient for the material to stay put?:confused:
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As I said , You will not want a Layer of compound, You only need it where the surface do not touch, If the stuff has to be a thick coat to stay put that is no good !

Heatsinks fret during thermal cycles a compound must stay flexible
 
JAKUS said:
As I said , You will not want a Layer of compound, You only need it where the surface do not touch, If the stuff has to be a thick coat to stay put that is no good !

Heatsinks fret during thermal cycles a compound must stay flexible
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Thick consistency isn't the same thing as a thick layer, not to mention it's only thick by comparison with AS5. Besides its proven to work better.
 
Hotwired said:
Thick consistency isn't the same thing as a thick layer, not to mention it's only thick by comparison with AS5. Besides its proven to work better.
Click to expand...

Of course it is :D

Hey, I'm not going to argue, I've told You Mechanically what the compound is there for, Use what ever You want :cool:
 
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