Question How to apply thermal paste

2336

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Feb 11, 2000
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Folks, I've been away awhile. I remember the generally accepted way of applying thermal paste was to apply a pea or lentil size blob and use a credit card to "squeegee" it down to the correct thickness on the CPU. Recently I've seen posts that state "just put a rice kernel size blob in the center of the CPU and just crank down the HSF unit - it'll spread everything out okay. What's the current generally accepted practice? I remember ever so carefully spreading Arctic Silver on Athlons, and just want to see what is safe with todays CPUs, - AMD and Intel. Thanks folks.
 

UsandThem

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It depends on the paste used, the cooler, and finally the size of the IHS.

A method that works great one way, might not work very well using different components.
 

Iron Woode

Elite Member
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Don't do it like they did in that Verge video. Looked like a Jackson Pollock painting.
 

UsandThem

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Fir

Senior member
Jan 15, 2010
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Pea method is antiquated on today's CPUs simply not because the heatspreader area is bigger but multiple dies below and (sometimes) not so efficient thermal coupling between said dies and the heatspreader. Ok, so that was a mouthful but the goal is to have the heatspreader completely covered with as thin of a layer as possible. Since the Nehalem days, I've been using the X method. Thinning lines stopping a few mm before the corners and thicker lines in the middle where the intersecting point is somewhat spherical and about 5-6mm in diameter.

Larger chips (eg TR4) require a twist to this technique either more spokes (think asterisk) or just painting a layer on. Some TIMs that are super pasty/viscous aren't going to be easy with this method. The syringe can be heated (gently) to thin it out some to make it easier. Put a coffee mug 3/4 filled with water in the microwave and nuke for 2 min, then (carefully) remove and place syringe in water. Make sure the cap is on TIGHT and watch the plunger for movement, if it looks like it's coming out on its own remove from the water, it's hot enough.

When you dismount the block, you should never see TIM past the edge of the heatspreader or running all over the place like a crazy cheeseburger. That's just too much paste. The minuscule gap between heatspreader and block is filled either way, but excessive paste just makes it more work to clean up AND in the case of electrically conductive pastes can present a real risk of destroying the board and cpu!
 

chrisjames61

Senior member
Dec 31, 2013
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Pea method is antiquated on today's CPUs simply not because the heatspreader area is bigger but multiple dies below and (sometimes) not so efficient thermal coupling between said dies and the heatspreader. Ok, so that was a mouthful but the goal is to have the heatspreader completely covered with as thin of a layer as possible. Since the Nehalem days, I've been using the X method. Thinning lines stopping a few mm before the corners and thicker lines in the middle where the intersecting point is somewhat spherical and about 5-6mm in diameter.

Larger chips (eg TR4) require a twist to this technique either more spokes (think asterisk) or just painting a layer on. Some TIMs that are super pasty/viscous aren't going to be easy with this method. The syringe can be heated (gently) to thin it out some to make it easier. Put a coffee mug 3/4 filled with water in the microwave and nuke for 2 min, then (carefully) remove and place syringe in water. Make sure the cap is on TIGHT and watch the plunger for movement, if it looks like it's coming out on its own remove from the water, it's hot enough.

When you dismount the block, you should never see TIM past the edge of the heatspreader or running all over the place like a crazy cheeseburger. That's just too much paste. The minuscule gap between heatspreader and block is filled either way, but excessive paste just makes it more work to clean up AND in the case of electrically conductive pastes can present a real risk of destroying the board and cpu!
The pea method still works even for cpu's with massive heat spreaders just add a tiny smidge more at the most. I have a couple Threadripper rigs and when I take the heatsink off, the heatspreader has a nice, even coating of tim from the pressure applied by the waterblock without pre spreading it.
 

chrisjames61

Senior member
Dec 31, 2013
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Poor guy. I bet he never makes another PC build video. :p

Edit: I found a shortened video of his build with added sound effects:


Tech Jesus messes around with different methods of paste here:
https://www.gamersnexus.net/guides/3346-thermal-paste-application-benchmark-too-much-thermal-paste

Although, don't do the "Too much" method. ;)


I don't want to beat up on the Verge guy but was he that delusional that he thought nobody would notice he didn't have a clue about building a pc? Or did he really believe he knew what he was doing? Either way it is mind boggling.
 

UsandThem

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May 4, 2000
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I don't want to beat up on the Verge guy but was he that delusional that he thought nobody would notice he didn't have a clue about building a pc? Or did he really believe he knew what he was doing? Either way it is mind boggling.
I think he was new to building PCs, and way over-confident with his experience in doing so. I just can't believe that anyone at The Verge didn't spot the issues, and basically threw him to the internet wolves. :oops:
 
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Markfw

CPU Moderator, VC&G Moderator, Elite Member
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Did you notice that he spelled dual as "duel" ? (or was that my CC in error)
 

thor23

Member
Jul 13, 2019
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Doesn't matter too much just don't use to little thermal paste. I think a small X is the most foolproof method.
 

sdifox

No Lifer
Sep 30, 2005
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You shouldn't have to put more than pea size. Remember they are filler material for imperfect surfaces.
 

Campy

Senior member
Jun 25, 2010
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Just use whichever technique you are comfortable with. It's better to use a little bit too much than to use too little, and don't use an electrically conductive paste. Once you get the cooler on with correct mounting pressure it will spread the paste to a thin layer. I use Thermal Grizzly Kryonaut paste, it spreads very easily.


edit: That Verge guy actually is completely delusional
 
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Fir

Senior member
Jan 15, 2010
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I guess I'm too stingy, after all a 'pea' is considerably larger than any glob I've used. Rice may be even a stretch so there's that.

I remember about 10 years ago buying some Zalmann stuff that came in a bottle with a brush and it was applied like nail polish. I actually liked how easy it was to apply and clean up. I was using Tuniq, Prolimatech, and Arctic Silver 5 at the time and the results were very similar.

And now they have these graphite pads that can be used essentially over and over again as long as they aren't messed up. How times have changed!
 

GodisanAtheist

Platinum Member
Nov 16, 2006
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Back in the day I would always do the "even coat using the edge of an old gift card" technique, but I was also much more concerned with squeezing every drop out of my OC back then (even if paste application wasn't really the culprit).

For a while now I've done the ole' pea sized blob (and remember that a pea is much smaller than it seems like in your mind's eye) on the center of the spreader and just mash it down with the heat sink.

Do I get that last 100-200mhz out of my OC? No. Do I really care? Not really.

Some good points raised about MCM packages that might warrant going back to the smear method that covers the heat spreader edge to edge, I'll likely do that when I put together my next build (99% likely it will be AMD).
 

Markfw

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For me, for many years, even before threadripper, I just use my finger... I put the thinnest coat I can get on the entire surface. It has done me well for over 20 years. The brush that fir mentioned would do exactly the same thing I think. It assures a thin even coat that works on ALL CPU sizes. Threadripper is the biggest problem (and EPYC) without using this method. The paste is too thick to spread itself evenly using the pea method.
 

ItsFlybye

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Apr 30, 2018
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I used to use a small plastic spreader to evenly spread across the CPU for that thin layer.

I thought the pea was enough, though. Should I upgrade to a black bean or lima bean?
 

Markfw

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I used to use a small plastic spreader to evenly spread across the CPU for that thin layer.

I thought the pea was enough, though. Should I upgrade to a black bean or lima bean?
Since CPU sizes vary so much, see my post above yours. The answer would be "it depends".
 

amrnuke

Senior member
Apr 24, 2019
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So you're telling me I shouldn't cover the CPU with thermal paste like I cover a chocolate cake with frosting? Hmm...
 

Markfw

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So you're telling me I shouldn't cover the CPU with thermal paste like I cover a chocolate cake with frosting? Hmm...
Not sure if this was directed at me, but, no, the thinnest layer of paste with full cpu HSF covering is what you want.
 

mopardude87

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Oct 22, 2018
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I have been religiously using AS5 since 2006, super easy put a little over a pea on there and i use my fingers or credit card and cover entire IHS. I love AS5 cause i got applications on chips going back to 2012 still fine on that paste.

As long as the IHS gets covered,i find temps are never a issue and stay well in the green.
 
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