Heat sink adhesive

[midhun]

Hello all,

I have a noob question regarding heat sinks.

I am looking to buy some heat sinks for Raspberry Pi 3. But my question is, how will I install my heat sink?

If I choose glue, then wouldnt the glue turn into liquid when the processor generates heat before heat sink cools it? If yes, then if the glue moves to any part of the circuitry, would it spoil Raspberry Pi 3?

Can someone throw some light on best practices on installing heat sinks? Is glue method fine? If not, does a double sided tape do the job?

Thanks,
Midhun.

[ghans]

There is so called "thermal adhesive". You should never
use anything different or you might overheat your Pi.

Regular adhesive is definitly the wrong kind.

ghans

[piglet]

Most come with 3M thermal tape on them already. You just peel off the backing and stick them on.

I got these ones - now selling for 26p including delivery from China....

[GeoffreyF]

In addition to what is already offered, I don't think a heat sink is needed except if you are going to be overclocking or running really complex software. If putting a finger on the chip doesn't feel more than warm, relax and don't bother.

Heat sinks also don't work very well if there isn't air circulation as from a fan. This is especially so if it's enclosed.

However, heat sinks look cool so carry on. As was said, ONLY use adhesives approved for this particular purpose.

[MarkHaysHarris777]

Most come with 3M thermal tape on them already.

I have not found any yet that did not have the adhesive tape already in place (I've used four different types, from several different manufacturers) Just peal the paper backings off and you're good to go.

I would also add, use forceps to place the heatsink... not your fingers. I have found that once they're stuck down they don't move easily after that; get them right the first try.

Heatsinks are optional (except on the PI 3B) where they are required... unless you want your PI to throttle under load.

[midhun]

Thank you all for valuable inputs.

How many heat sinks do I need for Raspberry Pi 3?

I notice I need two on the top side of Raspberry Pi 3. One for SOC and one for USB Hub processor. Do I need one on the bottom side too?

Just out of curiosity, what is the processor on the bottom side?

[RaTTuS]

all you need is one on the main SOC
the Lan9514 usb / ethernet does not need one
the RAM underneath does not need one

[hootie]

Pretty soon we're going to see a water cooled Pi

[MarkHaysHarris777]

Pretty soon we're going to see a water cooled Pi

I think Rive is already working on it... his wife is complaining about the cooling tower in the garage.

[midhun]

Thank you all for your inputs.

[lpsw]

I've never had put a heat sink on any of my Pis. No need, for me (low power guy). But I've install a few on other platforms
But if I had to, I'd strip the adhesive that comes on the heat sinks, carefully, with a razor, and clean it with isopropyl alcohol.
Apply a thin layer of a decent paste like Arctic Silver. If it's worth the effort for you to install a heat sink, might as well do it right.

[ric96]

I recommend what RS component recommends: http://in.rsdelivers.com/product/abl-co ... 00888.aspx

[Rive]

I've never had put a heat sink on any of my Pis. No need, for me (low power guy). But I've install a few on other platforms
But if I had to, I'd strip the adhesive that comes on the heat sinks, carefully, with a razor, and clean it with isopropyl alcohol.
Apply a thin layer of a decent paste like Arctic Silver. If it's worth the effort for you to install a heat sink, might as well do it right.

I did that myself... and it is a bad idea.(unless you plan on leaving pi3 flat)

The heat sink will move/slide when hot, and I compared AS5 versus pad/tape...no difference for the most part temp-wise.

Here is how I did mine
viewtopic.php?p=952371#p952371

[Pithagoros]

Heatsinks are optional (except on the PI 3B) where they are required... unless you want your PI to throttle under load.

Definitely not required on my Pi 3Bs, I don't use heatisinks and the highest temperature I've seen is 68C.

[Rive]

Pretty soon we're going to see a water cooled Pi

I think Rive is already working on it... his wife is complaining about the cooling tower in the garage.

You are too funny... but I like the idea

[lpsw]

I've never had put a heat sink on any of my Pis. No need, for me (low power guy). But I've install a few on other platforms
But if I had to, I'd strip the adhesive that comes on the heat sinks, carefully, with a razor, and clean it with isopropyl alcohol.
Apply a thin layer of a decent paste like Arctic Silver. If it's worth the effort for you to install a heat sink, might as well do it right.

I did that myself... and it is a bad idea.(unless you plan on leaving pi3 flat)

The heat sink will move/slide when hot, and I compared AS5 versus pad/tape...no difference for the most part temp-wise.

Here is how I did mine
viewtopic.php?p=952371#p952371

You are absolutely right. You need to use an adhesive variety. Just something better than what comes on the sinks.

[Rive]

You are absolutely right. You need to use an adhesive variety. Just something better than what comes on the sinks.

With adhesive, be sure because once on, you may never be able to get it off.

[lpsw]

Right...it can be done, but not easy. And certainly not recommended for a $900 chip but that's another deal.

[MarkHaysHarris777]

Heatsinks are optional (except on the PI 3B) where they are required... unless you want your PI to throttle under load.

Definitely not required on my Pi 3Bs, I don't use heatisinks and the highest temperature I've seen is 68C.

You haven't loaded it yet (this is not a matter of debate either... well proven, and well understood).

If you load your PI it will go to 80c and it will throttle. Of course you can do what you wish... but don't try to influence other people (especially when they have a valid concern) when your advice might cause harm (do no harm!).

Anyway, as always YMMV

[Heater]

MarkHaysHarris777,

You haven't loaded it yet (this is not a matter of debate either... well proven, and well understood).

Not well proven and well understood at all. Not by me anyway.

Today I fired up a new Pi 3 and set it to calculating 100,000,000 digits of Pi with gmp-chudnovsky.

It did not go 80C. It did not throttle. It did produce a correct result.

OK, I though, that's not enough, Let's run that again, twice on two cores at the same time.

I got up to 60C as reported by software and my IR thermometer.

What actually is it that you want to run to get the thing into melt-down?

[MarkHaysHarris777]

MarkHaysHarris777,

You haven't loaded it yet (this is not a matter of debate either... well proven, and well understood).

Not well proven and well understood at all. Not by me anyway ...

What actually is it that you want to run to get the thing into melt-down?

You're in the minority... there are just too many folks reporting the opposite (including me). Just for grins, is your PI cased? Is it open, or open in a small rack... or do you have a small baggie with an ice-cube sitting on top? (seriously?)

[DougieLawson]

Mine isn't cased and doesn't need a heat sink.

[davidcoton]

You're in the minority...

How do you know? I doubt that a high percentage of owners of non-overheating Pi3s will report that fact, while it is probably a much higher proportion of owners of overheating Pi3s who report. Looking at reports is at best anecdotal evidence, at worst misleading.

The fairest summary at the moment is along these lines:
1) Some Pi3s overheat easily. Probably not a high proportion, but the actual figure is unknown (at least outside Sony/RS/Farnell/RPF).
2) Some Pi3s overheat under heavy loads. The number is almost certainly higher than in (1), and could be over 50%. However, many users may never push their Pi3 to the extent necessary to reveal this behaviour (if it occurs on their Pi3).
3) Some Pi3s seem to remain below throttling temperature even with heavy loads. Again, the actual figure is unknown, and could be more or less than (1). It could even be the majority.
4) No patterns have been established to identify Pi3s prone to overheating, other than by testing.
5) Pi3s which overheat with particular tasks can usually be kept cool by using appropriate heatsinks, aided by a fan if necessary. Fans are more likely to be necessary where natural convective airflow is restricted.

I am hoping that one day (soon?) we will have some objective quantified information to put the claims and opinion in context. I quite agree that, if your Pi3 overheats in your context, then the world is a nasty place and Something Should Be Done.

DISCLAIMER: The above summary is my opinion, formed by reading other published opinions. It is not backed by any scientific investigation of a sample of Pi3s greater than one, or by any reproducible methodology on that one. I can be wrong.

[Heater]

MarkHaysHarris777,

No my Pi is not cased. It's in the open. The ambient temperature has been nudging 30C recently.

No ice cubes, no sign of stress, nothing bad happening.

I took the trouble to monitor things after reading all the tails of woe I have been reading here.

No woe yet,

What do I have to do to fry this thing?

[Rive]

No my Pi is not cased. It's in the open. The ambient temperature has been nudging 30C recently.
What do I have to do to fry this thing?

Put a full load on it, and then tell us if it overheats. A non-overheating, adequately powered stock Pi3 should pass with at least 6 Gflops (an overclocked pi3 will pass at 6.6-6.7 Gflops).

Set gpu mem to 48, and reboot before run

Code: Select all

sudo apt-get install libmpich-dev
wget http://web.eece.maine.edu/~vweaver/junk/pi3_hpl.tar.gz
tar -xvzf pi3_hpl.tar.gz 
chmod +x xhpl

Run:

Code: Select all

while true; do vcgencmd measure_clock arm; vcgencmd measure_temp; sleep 2; done& ./xhpl