Thermal Paste

[pcboardguy]

My roommate has a HP Pavillion dv6 3033cl and the cooling fan (with attached heat sink) is dead. A replacement is on its way. I'm more of a software guy than a hardware guy and haven't ever used thermal paste. When we get it, do I just apply a small amount to the heat sink (where it goes to the processor) and put it back in place?

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Flex PCB | PC Board Guy

 

[Topweasel]

My roommate has a HP Pavillion dv6 3033cl and the cooling fan (with attached heat sink) is dead. A replacement is on its way. I'm more of a software guy than a hardware guy and haven't ever used thermal paste. When we get it, do I just apply a small amount to the heat sink (where it goes to the processor) and put it back in place?

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Flex PCB | PC Board Guy

Other way around a small amount, probably about as much as a green pea on the CPU, so that when you mount the HSF it will push down on it and spread it over the heat spreader on the CPU.

 

[BrightCandle]

Other way around a small amount, probably about as much as a green pea on the CPU, so that when you mount the HSF it will push down on it and spread it over the heat spreader on the CPU.

Should be about the size of a dry grain of rice, a pea sized is way to much.

 

[aaksheytalwar]

I usually apply thermal paste to both the CPU and Cooler, works best that way. Actually, I get somebody to do that for me. And I have bad experience with applying less thermal paste but never had a bad experience with applying too much thermal paste.

I get reasonable temperatures only if an entire spread out layer has been spread on both surfaces, at least 3.5 gm per application.

 

[Harvey]

I usually apply thermal paste to both the CPU and Cooler, works best that way. Actually, I get somebody to do that for me. And I have bad experience with applying less thermal paste but never had a bad experience with applying too much thermal paste.

Sorry, but that is bad advice. Thermal compound is intended to fill microscopic gaps between the surface of the HS and the chip. Anything more will impede thermal contact, not improve it.

Try Arctic Silver 5 or one of the other known good ones. If there is any residue from a previous application, Windex works well to remove old compound.

When you apply the new stuff, use a VERY thin coating. I usually put a small BB size drop on the mating surface of the chip and use my finger to spread it evenly. Windex removes it from fingers, too.

 

[Topweasel]

Should be about the size of a dry grain of rice, a pea sized is way to much.

Depends on the stuff you are using an how malible it is. Pea size shouldn't on any of them droop off the side, but I have seen several including on this forum that the the rice size doesn't spread all the way across the spreader. Really it shouldn't make a big difference either way, we are literally talking about maybe at worst doubling up on TIM on what is already a small amount.

Important question, the grain, cooked or dry?

 

[Topweasel]

Sorry, but that is bad advice. Thermal compound is intended to fill microscopic gaps between the surface of the HS and the chip. Anything more will impede thermal contact, not improve it.

Try Arctic Silver 5 or one of the other known good ones. If there is any residue from a previous application, Windex works well to remove old compound.

When you apply the new stuff, use a VERY thin coating. I usually put a small BB size drop on the mating surface of the chip and use my finger to spread it evenly. Windex removes it from fingers, too.

Shouldn't do it this way either. Introduces air bubbles. Should be one solid buble that spreads with the heatink accross pushing the air out the side as apply the force needed to properly mount it.

 

[Harvey]

Sorry, but that is bad advice. Thermal compound is intended to fill microscopic gaps between the surface of the HS and the chip. Anything more will impede thermal contact, not improve it.

Try Arctic Silver 5 or one of the other known good ones. If there is any residue from a previous application, Windex works well to remove old compound.

When you apply the new stuff, use a VERY thin coating. I usually put a small BB size drop on the mating surface of the chip and use my finger to spread it evenly. Windex removes it from fingers, too.

Shouldn't do it this way either. Introduces air bubbles. Should be one solid buble that spreads with the heatink accross pushing the air out the side as apply the force needed to properly mount it.

Not at all. When I said "a VERY thin coat," I meant A VERY THIN coat, too thin for bubbles. My experience is with Arctic Silver 5, which is very liquid, so any possible remaining bubbles are removed by the simple slight movement of the HS across the mating surface while positioning it on the chip.

 

[Topweasel]

Not at all. When I said "a VERY thin coat," I meant A VERY THIN coat, too thin for bubbles. My experience is with Arctic Silver 5, which is very liquid, so any possible remaining bubbles are removed by the simple slight movement of the HS across the mating surface while positioning it on the chip.

True AS 5 is pretty liquidy. But some of the better stuff this day in age is pretty thick.

 

[Don Karnage]

Pea size on the middle of the CPU

 

[bbs lm-r]

Make sure to clean the old stuff off the CPU.

And don't sweat it, a little goes a long way.

 

[VirtualLarry]

True AS 5 is pretty liquidy. But some of the better stuff this day in age is pretty thick.

How liquidy do you mean? If I put a drop on the center of the heatsink, and then tilt it back and forth, it doesn't run off to one side.

My AS5 is more like toothpaste, than say, Ketchup.

 

[Topweasel]

How liquidy do you mean? If I put a drop on the center of the heatsink, and then tilt it back and forth, it doesn't run off to one side.

My AS5 is more like toothpaste, than say, Ketchup.

True. I used to use this really runny white paste in the past. Just saying that AS5 is closer to Ketchup then toothpaste in comparison to the MX-4 I used for the last two builds I did.

 

[richaron]

Too much is too much.. not only does it reduce thermal conductivity but my last lot (too much noctua goo) actually glued my cpu to the heatsink. I literally ripped the cpu out with the the heatsink without unhinging it.

 

[Topweasel]

Too much is too much.. not only does it reduce thermal conductivity but my last lot (too much noctua goo) actually glued my cpu to the heatsink. I literally ripped the cpu out with the the heatsink without unhinging it.

To little is worse. Thermal paste may not be as thermally conductive as direct contact. But if it doesn't spread completely then you have horrible air pockets everywhere. As for the dragging the CPU out. I ran into that in my socket 370 days once, I know many have and some ended up with bent pin. For almost all CPU's its suggested that you run the CPU for a couple minutes to heat up before you shut down and remove the heatsink.

 

[richaron]

To little is worse. Thermal paste may not be as thermally conductive as direct contact. But if it doesn't spread completely then you have horrible air pockets everywhere. As for the dragging the CPU out. I ran into that in my socket 370 days once, I know many have and some ended up with bent pin. For almost all CPU's its suggested that you run the CPU for a couple minutes to heat up before you shut down and remove the heatsink.

Yup I've heard the theory before. I'll try it next time before I want to kill my stupid heatsink for not giving me ~2mm more ram clearence while mounted.

Don't rebuild angry, or use too much paste, kids..

 

[Louisdaber]

There are several ways to do it actually. I ususally just put a drop on the center and let it spread when I put the cooler back on.

 

[pcboardguy]

Thanks for all of your help.
I enjoyed the talk of ketchup and toothpaste. I think the real question here is not if the rice is cooked or not, but are we talking about ketchup or catsup?
We did get the Arctic Silver 5 and used rubbing alcohol to clean off the old thermal paste.
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Flex PCB | PC Board Guy

 

[Topweasel]

Thanks for all of your help.
I enjoyed the talk of ketchup and toothpaste. I think the real question here is not if the rice is cooked or not, but are we talking about ketchup or catsup?
We did get the Arctic Silver 5 and used rubbing alcohol to clean off the old thermal paste.
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Flex PCB | PC Board Guy

Ketchup, real men don't use catsup.

 

[BrightCandle]

Uncooked rice in the centre of the processor. The pressure of mounting the Heatsink is so high these days that pretty much regardless of the viscosity of the paste it will be spread to where it needs to go. Some pastes have different advice but in a load of tests that various sites have done this proves to be the most reliable way to get a decent connection.

Less is best, or you'll be ruining the metal on metal contact that your making.

 

[aaksheytalwar]

I stand by what I said. I have tried all xtremes, very little, moderate, lots and lots was what got the temperature the best. And I have tried it several times. A 3.5gm injection is pretty much the minimum you need for best thermals, a single application

 

[aaksheytalwar]

As5 is electrically conducting. I wouldn't use it even if you paid me. Get prolimatech or arctic mx4, prolimatech is better

 

[Harvey]

I stand by what I said. I have tried all xtremes, very little, moderate, lots and lots was what got the temperature the best. And I have tried it several times. A 3.5gm injection is pretty much the minimum you need for best thermals, a single application

You can stand by what you said all you want. You can even stand on your head, but it won't change the laws of physics with respect to thermal transfer and the properties of thermal compound.

I wouldn't waste my time telling you that in public if you weren't posting bad advice to someone who needs better.

 

[BoomerD]

http://benchmarkreviews.com/index.php?option=com_content&task=view&id=170&Itemid=38

 

[serpretetsky]

http://www.youtube.com/watch?v=EyXLu1Ms-q4
video of effects of different application methods and amounts.

I usually say it doesn't really matter that much how much you apply, as long as these two criteria are met
1) If there's a heaspreader, the majority of the chip is covered(after compression), if its a naked core, the entire core is covered (after compression)
2) if the paste is electrically conductive or capactive, make sure you don't put excess paste on that may be squeezed out and fall on some traces.

As for the application method, whatever floats your boat. some pastes do better with the pea or line method, others do better flattening it out first.