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Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Wed Jun 26, 2019 6:14 pm
by Beorn_Bear
As the Raspberry Pi 4 will be hotter than Raspberry Pi 3 B+, would a simple heatsink make any difference?! Would it be better to use a fan or flirc case?! Are there any comparisons made yet?!

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Wed Jun 26, 2019 6:19 pm
by echmain
I don't believe the Pi 4 will fit into a [current model] FLIRC case (unless they've already updated it).

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Wed Jun 26, 2019 6:51 pm
by jbudd
You can pre-order a flirc case for the Pi 4 on their US website.

I suspect that cooling is going to be an issue with the Pi 4. No scientific basis for that opinion, just a burned fingertip

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Wed Jun 26, 2019 7:58 pm
by wh7qq
The answer depends on what you are doing with the RPi 4. Small heat-sinks made a big difference on my RPi 3B but the heat-sink adhesive tapes tend to be a better insulator than conductor. I attached mine with Arctic brand epoxy and went from frequent throttles on web pages with lots of java crap to just below 60C worst case.

That said, the RPi 4 has a maximum operating temp of 50 C according to their published specs so it may require both sink and fan to keep it below that line under normal conditions. With nothing to check, hard to say if a Flirc style case would have enough thermal mass and contact area to do the job alone and they never have supported a fan.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Wed Jun 26, 2019 10:12 pm
by Imperf3kt
wh7qq wrote:
Wed Jun 26, 2019 7:58 pm
That said, the RPi 4 has a maximum operating temp of 50 C according to their published specs so it may require both sink and fan to keep it below that line under normal conditions.
Where did you read that. The manual I read says 85°C like all previous Pi models.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Thu Jun 27, 2019 2:20 am
by Dygear
Just got the 2GB version of the rPi4 and the chip itself runs very warm to the touch. Like it's uncomfortable to put your finger on it. I don't remember the rPi3+ being this uncomfortable. With that said I'm actually pretty worried about the Flirc Case. I pre-ordered the new case for the rPi4 and I'm not sure it's going to be enough. My use case hammers the CPU, basically all of the time and that's why I used the Flirc Case as a massive heat sink for the tiny chip. On the rPi4 (2GB) right now in a room with controlled temperature (at 20°C) a with a few tabs open in Chrome, me writing this reply to you now, it's sitting at 76°C according to the little system tray icon graph. This chip runs hot. Granted it's entirely open to the air withing nothing but the ambient air in the room moving around cooling it. I'm not sure if the extra mass is going to be enough by itself. But, I'm not a hardware engineer, so I don't really know. Just my two cents and a data point for you to consider.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Thu Jun 27, 2019 3:25 am
by wh7qq
Imperf3kt wrote:
Wed Jun 26, 2019 10:12 pm
wh7qq wrote:
Wed Jun 26, 2019 7:58 pm
That said, the RPi 4 has a maximum operating temp of 50 C according to their published specs so it may require both sink and fan to keep it below that line under normal conditions.
Where did you read that. The manual I read says 85°C like all previous Pi models.
Somewhere on this site...it surprised me in that it was such a departure from previous models.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Thu Jun 27, 2019 3:28 am
by wh7qq
wh7qq wrote:
Thu Jun 27, 2019 3:25 am
Imperf3kt wrote:
Wed Jun 26, 2019 10:12 pm
wh7qq wrote:
Wed Jun 26, 2019 7:58 pm
That said, the RPi 4 has a maximum operating temp of 50 C according to their published specs so it may require both sink and fan to keep it below that line under normal conditions.
Where did you read that. The manual I read says 85°C like all previous Pi models.
Somewhere on this site...it surprised me in that it was such a departure from previous models and hard to maintain, but similar to other high powered boards I have seen with big heat sinks. Maybe a misprint? I don't keep track of every quote/source I encounter. Where did you read 85 (url)? It would be a relief.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Thu Jun 27, 2019 3:47 am
by Imperf3kt
I already told you, in the manual.

Specifically section 5.6 on the bottom of page 11

I am unable to find the link to download it in my history, so here's a screenshot.
Image

The 50°C you are referring to is ambient maximum.

If this isn't acceptable, here is a post by a Raspberry Pi engineer.
https://www.raspberrypi.org/forums/view ... 9#p1486109

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Thu Jun 27, 2019 8:53 am
by HawaiianPi
Dygear wrote:
Thu Jun 27, 2019 2:20 am
I'm actually pretty worried about the Flirc Case. I pre-ordered the new case for the rPi4 and I'm not sure it's going to be enough.
...
I'm not sure if the extra mass is going to be enough by itself. But, I'm not a hardware engineer, so I don't really know.
It's not the mass that helps, it's the surface area. That's why heatsinks have fins (less mass, but more surface area).

My experience with the Pi 3B (non-plus).

Fan alone is better than heatsink alone. Even the quiet Noctua NF-A4x10 5V fan kept my 3B below throttling temperatures. The problem with fans is that they they require additional power, quiet is not silent, and the system will get increasingly dusty over time.

Small passive heatsinks only prolong the inevitable throttling. Big ones may work, but can be tricky to mount and may interfere with installing a HAT or case. And of course, a passive heatsink in an enclosed case will not be as effective.

The Flirc case solved all of that for me. No extra power required, no throttling under heavy loads, and no accumulation of dust on the system board. I did have to dust the outside of the case from time to time to keep it looking good (and it does look good).

I'm still waiting for my back-ordered Pi 4B and pre-ordered Flirc case, but I have no doubt it will work well (large surface area).

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Thu Jun 27, 2019 11:47 am
by achrn
HawaiianPi wrote:
Thu Jun 27, 2019 8:53 am
Dygear wrote:
Thu Jun 27, 2019 2:20 am
I'm actually pretty worried about the Flirc Case. I pre-ordered the new case for the rPi4 and I'm not sure it's going to be enough.
...
I'm not sure if the extra mass is going to be enough by itself. But, I'm not a hardware engineer, so I don't really know.
It's not the mass that helps, it's the surface area. That's why heatsinks have fins (less mass, but more surface area).
Thermal mass will help with fluctuating thermal load, surely? If your Pi is doing anything oither than sustained number-crunching, then it will have a fluctuating computational load. Does that not translate to fluctuating thermal load?

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Thu Jun 27, 2019 7:06 pm
by Bruce Crowthorne
On my RPi4 /4G it was running at 85+ C
So I hacked an existing heatsink and attached it with heat sink compound, so it is now running at 55C
Still feels kind of hot ....

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Fri Jun 28, 2019 1:12 am
by wh7qq
Imperf3kt wrote:
Thu Jun 27, 2019 3:47 am
I already told you, in the manual.

Specifically section 5.6 on the bottom of page 11

The 50°C you are referring to is ambient maximum.

If this isn't acceptable, here is a post by a Raspberry Pi engineer.
https://www.raspberrypi.org/forums/view ... 9#p1486109
Indeed. I saw the 50 C and missed the rest...should have re-read it. Thanks, that is a relief. I had visions of some of the other SBCs with wall-to-wall heat-sink-fan assemblies on top.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Fri Jun 28, 2019 1:25 am
by Imperf3kt
With some of the recent posts, I'm starting to envisage myself cooking breakfast on a Pi4b2

Official frying pan hat anyone?

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Fri Jun 28, 2019 3:35 am
by Dygear
It's a fair point to say surface area is more important than mass.

My use case is that I use them as software defined radios, so it's a constant stream of numbers to crunch 24/7/365. I've actually had a Pi in operation for the past year doing exactly that in the Flirc case inside of an ambulance garage. That seems to be ok, but given the extra heat that the rPi 4 is producing, I'm not so sure. I'm very interested to see the actual results.

But that's all academic at this point, because for what ever reason I can't get my RTL dongles to mount on the rPi4. I think the software stack isn't quite there yet for it.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Fri Jun 28, 2019 3:53 am
by Gavinmc42
As "Desktop replacement".
Every Desktop I have ever had has a fan or two or three ;)
Did basic calc for 25C room, finger safe 55C = 32x32x16mm finned heatsink.
Go smaller with fan and summer in Oz.

But how much can be got out via those 4 mounting holes.
Copper spacers to big chuck of metal, ie mini desktop case?
Every bit of metal on that PCB is a heatsink now.

Hmm those fancy PC fans with LEDs are 120mm.
Pi PCB is 56mm wide so 50 or 60mm fan?
Can we get those clear ones in those sizes?

Overclocked and water cooled, that would be fun :lol:

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Fri Jun 28, 2019 4:02 am
by Imperf3kt
Gavinmc42 wrote:
Fri Jun 28, 2019 3:53 am
Overclocked and water cooled, that would be fun :lol:
Did that to a Pi3b, wasn't nearly as effective as expected despite the radiator being three times the size of the Pi.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Fri Jun 28, 2019 6:40 am
by pik33
I put my RPi4 into a case with a small 3cm fan powered form 3v3 so it rotates slow and doesn't generate any hearable noise unless in a silent room at night. The fan does its job keeping temperature at 50C idle and up to 65C loaded. No heatsink attached. to the CPU.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Fri Jun 28, 2019 6:49 am
by jamesh
pik33 wrote:
Fri Jun 28, 2019 6:40 am
I put my RPi4 into a case with a small 3cm fan powered form 3v3 so it rotates slow and doesn't generate any hearable noise unless in a silent room at night. The fan does its job keeping temperature at 50C idle and up to 65C loaded. No heatsink attached. to the CPU.
I think that is probably the best option. I use a PoE hat that keeps the Pi4 below 60.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Fri Jun 28, 2019 7:12 am
by PeterO
It is very noticeable how with just a small airflow over the USB and Ethernet connectors they stay much cooler to the touch. They certainly help to keep the temperature down.
Pi4FanSmall.png
Pi4FanSmall.png (54.88 KiB) Viewed 9919 times
That's a 12V fan under run at 5V so it's not spinning very fast and (as others have said) is very quiet. Temp. sitting at 45°C idle.
I need to find less temporary way to mount it ;)
PeterO

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Fri Jun 28, 2019 7:24 pm
by HawaiianPi
Gavinmc42 wrote:
Fri Jun 28, 2019 3:53 am
Pi PCB is 56mm wide so 50 or 60mm fan?
60mm fan fits well (width of Pi PCB mounting holes is not exact, but it's close enough). And there are 5V 60mm fans.
OP_RPi_CPU_fan_2.jpg
OP_RPi_CPU_fan_2.jpg (75.33 KiB) Viewed 9468 times

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Sat Jun 29, 2019 8:51 am
by pik33
This is my setup.
65396092_2372157356441807_8293426104471912448_n.jpg
65396092_2372157356441807_8293426104471912448_n.jpg (99.23 KiB) Viewed 9145 times

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Fri Aug 16, 2019 9:05 pm
by deanresin
Imperf3kt wrote:
Thu Jun 27, 2019 3:47 am
I already told you, in the manual.

Specifically section 5.6 on the bottom of page 11

I am unable to find the link to download it in my history, so here's a screenshot.
Image

The 50°C you are referring to is ambient maximum.

If this isn't acceptable, here is a post by a Raspberry Pi engineer.
https://www.raspberrypi.org/forums/view ... 9#p1486109
That is a big difference from "maximum operating temperature". When I turn on my RPI4 it will never operate below 50°C just sitting there turned on with no case.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Sat Aug 17, 2019 6:04 am
by hippie403
Youtube video of Pi 4 FLIRC case testing: https://youtu.be/vkLr08K0c1E Sounds like it is perfectly adequate. I've got one on order for my second Pi 4. I have a case with a small fan and 4 small heat sinks, idling at 42C ambient 22C.

Re: Raspberry Pi 4 Heatsink vs Fan vs Flirc Case

Posted: Sat Aug 17, 2019 7:04 am
by takyon
I dropped from about 60-64°C on the Pi 4 in sustained normal use with no case (sitting on top of the cardboard box it came in), to about 48-52°C with the Kodi FLIRC case (starts out less, but heats up to that). I think ambient is at least 24°C.

I would be interested to see someone plug the RTL-SDR dongle into it, once it actually works.