duraturk
Posts: 5
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Heatsink for RPI 3B+

Tue Jul 10, 2018 3:18 am

Hi,

Just ordered my first RPI, 3B+ and impatiently waiting it to be delivered.

I am not planning to overclock it but I will try to avoid thermal throttling as much as possible. I am not very keen on using a fan to cool it down. Since I wont be overclocking it, a decent heatsink solution should be good enough for me, i guess.

I researched some good heatsinks, though I haven't seen any thermal tests with the new 3B+, the owners of those seems to be very happy with their choice.

Here is a short list of what I have on my mind to use on mine. I would be very happy if people who have hands on experience with these solutions provides some feedback.

1- Flirc Case Gen 2
Some people says the temp difference it provides is insignificant but some owners totally disagree. There are some thermal tests with this case and RPI 3B but I haven't seen any tests performed with the new 3B+. So, I don't know what is significant and what is not. I believe I can apply thermal paste if I use this case rather than using the thermal tape it comes with.

According to what I read, thermal tapes doesn't transfer heat as good as the paste. I am guessing by using this case with thermal tape, I might get enough performance for what I need.

2- Kintaro Heatsink
Interesting design. Comes with a thermal paste rather than a tape. Have perfect reviews. No numbers, no testes and I really don't know if the review owners are using 3B or 3B+.

3- Adafruit 15x15x15 Heatsink

I might choose to use this large and tall heatsink. It looks like a heatsink that would make a real difference. Most HATs would not with due to the height but I don't plan to use any HATs with my RPI anyway (at least not yet). And again, it will not with to all cases as well.

I remember someone saying that he was happily using this heatsink with this case. I don't remember if he was using a 3B pi or the new 3B+ pi and I don't remember any test results or numbers. So, I really don't know what "happily using" refers to in terms of temperature.

Another question is whether attaching this heatsink with a thermal paste or with the thermal tape. While the thermal paste will help the heat transfer better, it does not adhere onto the chip as the tape would. This would not be a problem with Flirc case or with Kintora heatsink but I might be a problem with this heatsink & case solution. Who wants their heatsink move around.

I would :LOVE to hear from the owners of these solutions who are using them on a 3B+ RPI.

Thanks...

jamesh
Raspberry Pi Engineer & Forum Moderator
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Re: Heatsink for RPI 3B+

Tue Jul 10, 2018 6:29 am

Before adding a heatsink, use the 3b+ and see whether in your use case throttle or not. The entire PCB acts as a heatsink, so an extra may not be necessary.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Please direct all questions to the forum, I do not do support via PM.

jahboater
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Re: Heatsink for RPI 3B+

Tue Jul 10, 2018 6:54 am

Wow! This Kintaro heatsink is a new idea.
There are no mounting holes on the Pi for a heatsink so sticky tape is usually used.

The thermal management on the 3B+ is very good, the PCB ground plane acts as a heatsink. So as JamesH says, try it first and monitor the temps with "vcgencmd measure_temp".

I use the Adafruit 15mm cube heatsink. My board is mounted on edge in free air.
As far as I can see it is impossible with any normal load to make it throttle with this arrangement (that is all four cores flat out for hours). A deliberate stress test (such as cpuburn) will make it throttle a small amount, but thats not real work.

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Imperf3kt
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Re: Heatsink for RPI 3B+

Tue Jul 10, 2018 7:12 am

jahboater wrote:
Tue Jul 10, 2018 6:54 am
Wow! This Kintaro heatsink is a new idea.
There are no mounting holes on the Pi for a heatsink so sticky tape is usually used.

The thermal management on the 3B+ is very good, the PCB ground plane acts as a heatsink. So as JamesH says, try it first and monitor the temps with "vcgencmd measure_temp".

I use the Adafruit 15mm cube heatsink. My board is mounted on edge in free air.
As far as I can see it is impossible with any normal load to make it throttle with this arrangement (that is all four cores flat out for hours). A deliberate stress test (such as cpuburn) will make it throttle a small amount, but thats not real work.
Are you sure the throttling while running cpuburn is heat related? So far with my Pi3b (yes, not a 3b+), I haven't experienced any thermal throttling while running cpuburn. I do notice however, that an inadequate power supply or cable, will cause an undervolt event, which in turn appears to trigger throttling. At least, as far as my testing pointed out.

I'm with Jamesh on this, try it and see, before wasting money on an accessory (unless you just like the look of said accessory). Chances are that you honestly don't require it.
If it stays around 60℃ you're fine. If it sits around 70℃, its a bit hot, but still within safe operating limits. If it hits 85℃, it'll throttle, and impact performance, but you have to be seriously trying to reach this temperature if your Pi is relatively well ventilated.
Stop plugging your fan directly into the GPIO 5v
https://www.electronics-tutorials.ws/power/transient-suppression.html

jahboater
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Re: Heatsink for RPI 3B+

Tue Jul 10, 2018 7:19 am

Imperf3kt wrote:
Tue Jul 10, 2018 7:12 am
Are you sure the throttling while running cpuburn is heat related?
Most definitely. It is slightly over-clocked though:-

sdram_freq=500
core_freq=500
disable_l2cache=0
Imperf3kt wrote:
Tue Jul 10, 2018 7:12 am
If it stays around 60℃ you're fine. If it sits around 70℃, its a bit hot, but still within safe operating limits. If it hits 85℃, it'll throttle, and impact performance, but you have to be seriously trying to reach this temperature if your Pi is relatively well ventilated.
Thats all changed with the 3B+.
With the current release of Raspbian, it will throttle back at 60C. It will go from 1.4GHz down to 1.2GHz and lower the voltage at that point. Later if the temp reaches 80C it will start progressively throttling back a little bit at a time. I presume at 85C it will then drop down to 600MHz but I have never reached that with a 3B+.

Note the 60C lower limit may be overridden with "temp_soft_limit=70" in /boot/config.txt, to raise it to 70C as it was with the previous Raspbian release.

The increased thermal inertia with the new 3B+ means for normal short day-to-day tasks, heat is a non-issue.

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Imperf3kt
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Re: Heatsink for RPI 3B+

Tue Jul 10, 2018 11:16 am

Ah, right. Forgot they changed the soft throttle from 70 to 60 on a 3b+
Stop plugging your fan directly into the GPIO 5v
https://www.electronics-tutorials.ws/power/transient-suppression.html

duraturk
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Re: Heatsink for RPI 3B+

Wed Jul 11, 2018 1:36 am

Thanks all for the helpful feedback. I got way too excited and went ahead of myself. I will just use it and test it for a while, before I plan to purchase a heatsink.

@jahboater
Can we also do...

Code: Select all

"temp_soft_limit=75"
Will it work? and how smart is that? I mean it's a good idea to use a setting higher than 70.

Thanks....

bertlea
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Location: Hong Kong

Re: Heatsink for RPI 3B+

Wed Jul 11, 2018 1:42 am

No, setting it above 70 is not going to work as you wanted, according to the feed backs on the same questions I asked:

viewtopic.php?f=63&t=217056&p=1335599#p1335599

jahboater
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Re: Heatsink for RPI 3B+

Wed Jul 11, 2018 5:06 am

It is capped at 70C, if you set it to a higher value it remains at 70C.

Use "vcgencmd get_config int" to see what its actually been set to.

hippy
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Re: Heatsink for RPI 3B+

Wed Jul 11, 2018 2:12 pm

jahboater wrote:
Tue Jul 10, 2018 6:54 am
Wow! This Kintaro heatsink is a new idea.
It is similar to a heatsink I removed from a games console though that also had a low profile axial fan fitted it as well. Similar to the iUniker heatsink here ...

https://www.amazon.com/iUniker-Raspberr ... B07D3S4KBK

I guess that mazimises heat transfer and dispersal while keeping a low profile.

jahboater
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Re: Heatsink for RPI 3B+

Thu Jul 12, 2018 9:12 am

I purchased the Kintaro heat sink (purely for interest, my 3B+ was fine anyway).
https://www.amazon.com/dp/B07CTSNZYK/
It keeps my Pi3B+ (very approx) 10C cooler than the Adafruit 15mm cube heatsink.
It also cools the USB/Ethernet chip.
I am impressed!

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HawaiianPi
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Re: Heatsink for RPI 3B+

Thu Jul 12, 2018 11:31 am

The Flirc Gen2 works very well for me, and it's a great looking case!

You would not be able to use thermal compound. That only works well when the heatsink is in direct contact with the part being cooled, and there is a small gap with the Flirc. There are better thermal pads available, but try not to get carried away here. You're cooling a Raspberry Pi that runs on less than 13W (max), only about half of which is allocated to the system (<7W). You don't need Thermal Grizzly and a diamond heatsink to cool a Pi.

The main drawback to the Flirc is no easy access to the GPIO header. There is a slot in the bottom of the case to pass wires out, but you won't be able to use a HAT, and you'd need to remove the top of the case to change the wiring.

If you're not messing with GPIO much it's an awesome case. New shipments come with thermal pads for both the older 3B and the newer 3B+ models.
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?

Quad+Pi
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Re: Heatsink for RPI 3B+

Thu Jul 12, 2018 2:46 pm

Hi, I'm a Newbie to posting on this site, so I'm not sure if I can tag along and ask a question here about adding a heatsink to the 3B+?
I have 2 other Pi3Bs streaming music and videos with OSMC, both in double height clear cases, and my new 3B+ is running fine; now I want to add a HAT to the GPIO terminals which will give me a DAC for my music streaming the same as the other Pis. This HAT will shield the Broadcom processor and I'm thinking that it might cause a heat build-up. I was planning to add a copper heatsink like the other two devices but then I noticed a small hole in one corner of the metal lid they put on this new processor. I presume it has something to do with heat control but, despite searching all the FAQs I can't find any reference to it. I didn't want to add the heatsink and block the hole without knowing its purpose first in case my actions would be counter-productive thus "killing" my new Pi!
If this is not the correct thread, my apologies, if it is, could anyone shed any light on the matter please?

jahboater
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Re: Heatsink for RPI 3B+

Thu Jul 12, 2018 2:56 pm

The Kintaro heat sink is mounted with four bolts so a thermal compound is used instead of adhesive tape.
It came with some kind of metallic looking compound that was easy to apply.
Maybe I should have searched for a old tube of Arctic Silver 5 in my tool box, but this stuff seems to work.

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Imperf3kt
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Re: Heatsink for RPI 3B+

Thu Jul 12, 2018 9:39 pm

Quad+Pi wrote:
Thu Jul 12, 2018 2:46 pm
Hi, I'm a Newbie to posting on this site, so I'm not sure if I can tag along and ask a question here about adding a heatsink to the 3B+?
I have 2 other Pi3Bs streaming music and videos with OSMC, both in double height clear cases, and my new 3B+ is running fine; now I want to add a HAT to the GPIO terminals which will give me a DAC for my music streaming the same as the other Pis. This HAT will shield the Broadcom processor and I'm thinking that it might cause a heat build-up. I was planning to add a copper heatsink like the other two devices but then I noticed a small hole in one corner of the metal lid they put on this new processor. I presume it has something to do with heat control but, despite searching all the FAQs I can't find any reference to it. I didn't want to add the heatsink and block the hole without knowing its purpose first in case my actions would be counter-productive thus "killing" my new Pi!
If this is not the correct thread, my apologies, if it is, could anyone shed any light on the matter please?
That hole is used during production to allow gasses and vapors to escape from the bonding process.
You may cover it if you wish, it isn't a magic blue smoke vent.
Stop plugging your fan directly into the GPIO 5v
https://www.electronics-tutorials.ws/power/transient-suppression.html

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HawaiianPi
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Re: Heatsink for RPI 3B+

Thu Jul 12, 2018 10:21 pm

Imperf3kt wrote:
Thu Jul 12, 2018 9:39 pm
... it isn't a magic blue smoke vent.
Which is a good thing, because the magic blue smoke refill kit is no longer available from Sparkfun Electronics. ;)
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?

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Imperf3kt
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Re: Heatsink for RPI 3B+

Fri Jul 13, 2018 12:25 am

HawaiianPi wrote:
Thu Jul 12, 2018 10:21 pm
Imperf3kt wrote:
Thu Jul 12, 2018 9:39 pm
... it isn't a magic blue smoke vent.
Which is a good thing, because the magic blue smoke refill kit is no longer available from Sparkfun Electronics. ;)
I keenly await the day they restock though, as my Pi0w had a leak in the seal and ran out of magic blue smoke shortly after purchase.
I've considered substituting regular blue smoke, but I still require the applicator kit.
Maybe next April.
Last edited by Imperf3kt on Sat Jul 14, 2018 10:32 am, edited 1 time in total.
Stop plugging your fan directly into the GPIO 5v
https://www.electronics-tutorials.ws/power/transient-suppression.html

Quad+Pi
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Re: Heatsink for RPI 3B+

Fri Jul 13, 2018 7:07 am

Thank you folks; there are, among many others, two items I've tried to avoid in my hobbies - bright sparks and clouds of smoke (of any colour)!
Sticking the heatsinks in place now and on with my HAT, hoping for cool music streaming - ;~)

boyoh
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Re: Heatsink for RPI 3B+

Fri Jul 13, 2018 6:57 pm

duraturk wrote:
Tue Jul 10, 2018 3:18 am
Hi,

Just ordered my first RPI, 3B+ and impatiently waiting it to be delivered.

I am not planning to overclock it but I will try to avoid thermal throttling as much as possible. I am not very keen on using a fan to cool it down. Since I wont be overclocking it, a decent heatsink solution should be good enough for me, i guess.

I researched some good heatsinks, though I haven't seen any thermal tests with the new 3B+, the owners of those seems to be very happy with their choice.

Here is a short list of what I have on my mind to use on mine. I would be very happy if people who have hands on experience with these solutions provides some feedback.

1- Flirc Case Gen 2
Some people says the temp difference it provides is insignificant but some owners totally disagree. There are some thermal tests with this case and RPI 3B but I haven't seen any tests performed with the new 3B+. So, I don't know what is significant and what is not. I believe I can apply thermal paste if I use this case rather than using the thermal tape it comes with.

According to what I read, thermal tapes doesn't transfer heat as good as the paste. I am guessing by using this case with thermal tape, I might get enough performance for what I need.

2- Kintaro Heatsink
Interesting design. Comes with a thermal paste rather than a tape. Have perfect reviews. No numbers, no testes and I really don't know if the review owners are using 3B or 3B+.

3- Adafruit 15x15x15 Heatsink

I might choose to use this large and tall heatsink. It looks like a heatsink that would make a real difference. Most HATs would not with due to the height but I don't plan to use any HATs with my RPI anyway (at least not yet). And again, it will not with to all cases as well.

I remember someone saying that he was happily using this heatsink with this case. I don't remember if he was using a 3B pi or the new 3B+ pi and I don't remember any test results or numbers. So, I really don't know what "happily using" refers to in terms of temperature.

Another question is whether attaching this heatsink with a thermal paste or with the thermal tape. While the thermal paste will help the heat transfer better, it does not adhere onto the chip as the tape would. This would not be a problem with Flirc case or with Kintora heatsink but I might be a problem with this heatsink & case solution. Who wants their heatsink move around.

I would :LOVE to hear from the owners of these solutions who are using them on a 3B+ RPI.

Thanks...

If you use the Pi as it should be , there is no need for a fan or extra heat sinks
You only have to look at the size of the Pi to tell you it is not meant to run power
hungary circuits directly,, Just use the Pi to switch low power signals to con troll
Buffer stages for high power circuits using a separate power supply.

Fitting a fan on the on the Pi is counter productive, as this will ad load to the
Pi power supply, If you still intend fitting a fan , use a separate power supply.

Regards BoyOh Retired Electrical / Electronic Technician
BoyOh ( Selby, North Yorkshire.UK)
Some Times Right Some Times Wrong

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HawaiianPi
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Re: Heatsink for RPI 3B+

Sat Jul 14, 2018 3:24 am

Imperf3kt wrote:
Fri Jul 13, 2018 12:25 am
I keenly await the day they restock though...
I believe the destruction of the rain forest has eliminated their supply of the rare spores. ;) :lol:
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?

duraturk
Posts: 5
Joined: Mon Jul 09, 2018 9:25 pm

Re: Heatsink for RPI 3B+

Tue Jul 17, 2018 2:34 pm

I just received my RPI last week and since then I am playing with it. People say I wouldn't need a heatsink under regular, normal load. Ohh well, I don't know what is my normal, regular load is yet. Like I said, I am still playing with it. I learned not to browse the internet with more than one tab.

Checking my temp regularly with...

Code: Select all

vcgencmd measure_temp
Not using any tests or benchmarks. Just my own heavy load and I see temps up to 74C. It usually goes between 68C and 72C. I decided that a heatsink would be nice, efficient and sufficient.

Leaning more over to Kintaro Heatsink. Esspecially after it has been tested and proved to be useful.

@jahboater
The 10C cooler is on top of how much your 15x15 heatsink cools it down, right?
My guestimate would be like 15C or more cooler when compared to a no-heatsink situation.
Isn't that impressive?
What you think our chances would be to use this with a case.
I don't think it will fit in a regular sized case.
What you think?

Thanks....
jahboater wrote:
Thu Jul 12, 2018 9:12 am
I purchased the Kintaro heat sink (purely for interest, my 3B+ was fine anyway).
https://www.amazon.com/dp/B07CTSNZYK/
It keeps my Pi3B+ (very approx) 10C cooler than the Adafruit 15mm cube heatsink.
It also cools the USB/Ethernet chip.
I am impressed!

jahboater
Posts: 3027
Joined: Wed Feb 04, 2015 6:38 pm

Re: Heatsink for RPI 3B+

Tue Jul 17, 2018 3:58 pm

duraturk wrote:
Tue Jul 17, 2018 2:34 pm
The 10C cooler is on top of how much your 15x15 heatsink cools it down, right?
Yes.
duraturk wrote:
Tue Jul 17, 2018 2:34 pm
My guestimate would be like 15C or more cooler when compared to a no-heatsink situation.
To be honest I don't know about that as I have never run a Pi3B+ without a heatsink.
It takes seconds to stick on one of the Adafruit heat sinks, and it can do no harm.
Your guess sounds plausible though.
Note that my Pi3's run in free air, the board is mounted vertically, and the heat sink fins are aligned vertically.
Even though they are headless, I plug in some cables to dissipate a little more heat.
Finally, I stick a 15mm cube Adafruit heatsink on the memory as I believe the refresh rate depends on its temperature.
duraturk wrote:
Tue Jul 17, 2018 2:34 pm
What you think our chances would be to use this with a case.
I don't think it will fit in a regular sized case.
Don't Kintaro make cases that will accept their heatsink?

jahboater
Posts: 3027
Joined: Wed Feb 04, 2015 6:38 pm

Re: Heatsink for RPI 3B+

Tue Jul 17, 2018 4:06 pm

duraturk wrote:
Tue Jul 17, 2018 2:34 pm
Checking my temp regularly with...

Code: Select all

vcgencmd measure_temp
This little script is handy for minitoring a Pi:

Code: Select all

#!/bin/bash
Counter=14
DisplayHeader="Time      Temp    CPU        Throttle        Vcore"
while true ; do
  let Counter++
  if [ ${Counter} -eq 15 ]; then
    echo -e "${DisplayHeader}"
    Counter=0
  fi
  Health=$(perl -e "printf \"%19b\n\", $(vcgencmd get_throttled | cut -f2 -d=)")
  Temp=$(vcgencmd measure_temp | cut -f2 -d=)
  RealClockspeed=$(vcgencmd measure_clock arm | awk -F"=" '{printf ("%0.0f",$2/1000000); }' )
  CoreVoltage=$(vcgencmd measure_volts | cut -f2 -d= | sed 's/000//')
  echo -e "$(date '+%H:%M:%S') ${Temp} $(printf '%4s' ${RealClockspeed})MHz $(printf '%019d' ${Health}) ${CoreVoltage}"
  sleep 5
done
# SysFSClockspeed=$(awk '{printf ("%0.0f",$1/1000); }' </sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq)
and this will get your Pi3+ toasty hot fairly quickly:

Code: Select all

wget https://raw.githubusercontent.com/ssvb/cpuburn-arm/master/cpuburn-a53.S
gcc -o cpuburn-a53 cpuburn-a53.S
./cpuburn-a53
With the Kintaro heatsink this stabilizes out at around 70C which I am pleased with.
It means no normal workload can ever cause my Pi to throttle back!

jahboater
Posts: 3027
Joined: Wed Feb 04, 2015 6:38 pm

Re: Heatsink for RPI 3B+

Tue Jul 17, 2018 5:34 pm

I just ran a CPU heavy task (one core) on two Pi3+ and averaged out the temperature readings for a bit.

Adafruit 15mm cube heat sink: 57.24C
Kintaro heat sink: 45.4C
11.84C improvement with the bigger heat sink, and thermal paste instead of sticky tape.

The Adafruit one is close to throttling, and that just with one core maxed out.

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