

Ask HN: How Should I Apply Thermal Paste? - guilamu

The Internet is quite confusing on this topic. Some say you should apply just a pea, some that you should spread it with on applicator on the whole surface (hence creating &quot;evil&quot; air bubbles?). They can&#x27;t even agree on which part you should apply the thermal paste on: the CPU or the cooler? Thanks a lot for your input.
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MattBearman
It's been about 10 years since I built a PC, but I always did the following,
and never had any cooling issues - in fact, I got quite good overclocking
results:

Using plastic gloves (or just put a plastic bag over your hand) spread a
REALLY thin layer over the cooler using your finger. This is simply just to
fill any small grooves in the coolers surface. If you lap your cooler you
don't need to do this.

Using a credit card spread a layer around 1mm thick on CPU, the main thing
here is to just try and cover the whole area of the CPU that comes into
contact with the cooler.

The most important thing is not to fret too much about this. Once you've put
it all together, run a stress test and keep an eye on the CPU temp, if it goes
too high, just clean the paste off and try again :)

~~~
guilamu
Thanks for your reply, MattBearman.

According to ArcticSilver (
[http://www.arcticsilver.com/pdf/appmeth/int/vl/intel_app_met...](http://www.arcticsilver.com/pdf/appmeth/int/vl/intel_app_method_vertical_line_v1.1.pdf)
) all CPU covered with an aluminium plate should have their thermal paste just
put in a single vertical line in the center.

They also talk about the line surface spread method you're talking about but
only for mobile CPUs.

My fear is that by spreading the paste with gloves I'd somehow add some air in
the paste, resulting in really bad thermal conductivity.

It seems your method is the way to go, though:
[http://overclocking.guide/thermal-paste-
roundup-2015-47-prod...](http://overclocking.guide/thermal-paste-
roundup-2015-47-products-tested-with-air-cooling-and-liquid-nitrogen-ln2/4/)

~~~
MattBearman
Interesting, as ArcticSilver was my paste of choice, and my method was based
on what they used to recommend, it seems things have changed in the last 10
years - I'd probably go with what the ArcticSilver instructions say.

As for using gloves, you won't add an air pocket, as the gloves are only used
for applying a really thin coating to the heatsink. By really thin, I mean
just enough to be visible on the heatsink, while still being able to see the
heatsink surface through the thermal paste. That should be enough to fill any
gaps in the heatsink surface.

------
auganov
[https://www.pugetsystems.com/labs/articles/Thermal-Paste-
App...](https://www.pugetsystems.com/labs/articles/Thermal-Paste-Application-
Techniques-170/)

TLDR: if in doubt just use the small dot in the center method. the X if you're
feeling creative

And yes, you just apply it to the cpu and when the heatsink presses on the cpu
it will do the spreading by itself

------
kek918
When I had a Dell technician visiting and replacing CPU on a laptop he applied
it using the X-method. Personally I've only tried the dot in the middle method
which has worked great for me, but when I look at video tests through a glass
plate it seems the X method is a bit safer/more accurate.

If there are instructions available from the supplier I'd recommend sticking
to that though because it seems like the different thermal paste brands
behaves differently in terms of spreading.

------
borplk
My opinion based on experience:

Apply a pea-sized drop in the very center and you are done! (and resist the
temptation to make it juust a little larger)

The pressure will spread it out evenly.

There was a video I saw where they did this using glass so you could how the
paste spreads.

