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Way to keep your cool running a Raspberry Pi 4 (2019)

jeffgeerling.com

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Re: Way to keep your cool running a Raspberry Pi 4 (2019)

#91

Post by Arnt »

NortySpock wrote: post #79
Arnt wrote: post #24

Earlier quoted context omitted.

Would you describe that flirc case as complicated? To a naïve layman, it seems like the smallest all-metal case that'll fit the rpi4, made so that the metal acts as a heatsink. Which may be more heatsink area than a 15W CPU needs, but not bigger case area than is needed. Is there something I'm missing?

I believe the FLIRC case is custom designed for the RPi4, not just "happens to fit" as you imply. Otherwise you have it correct; it's an aluminum case that mates down onto the CPU for direct passive cooling. Note that it's clearly an injection-molded aluminum top-half and the bottom-half is plastic, just used to keep the dust out. I would describe it as simple and elegant; fit for purpose. Otherwise I'm quite happy t…

I did not mean to imply that. Rather, if anything, that it seems to be based on an insight that a metal shape that's enough to enclose also works as cooling.

What a pity that there's plastic on the bottom.

Re: Way to keep your cool running a Raspberry Pi 4 (2019)

#92

Post by washadjeffmad »

LeoPanthera wrote: post #77
rc4hobby wrote: post #21

Thermal engineer here. There absolutely no need to use fan cooling, humongous heatsinks or harebrained temperature controller schemes to cool the raspberry pi 4. All that is needed is a small heatsink to slightly decrease the thermal resistance to ambient air, to stay below the thermal throttling threshold. Anything more complicated than that is a pointless exercise in pointlessness.

Did you read the article? He tested a heatsink. I'll quote the relevant part. > Heatsinks will generally shave 5-10°C off the highest temperatures you encounter, which is significant, but you still need to have air moving across the heatsink for it to do anything. This means either a fully open Pi (great for testing or tinkering, not so great for a semi-permanent installation), a well-ventilated case (with slots or h…

He doesn't have much of a methodology and seems to have missed a key point of the heatsink: orientation.

If he'd mounted his Pis' GPIO parallel to the ground, heatsink fans perpendicular to it, he would have found his missing convection with or without a heatsink.

This is what I do, and mine haven't reported >45`F ambient under peak load in a passively ventilated area. There is no issue with heat removal with enough air space.

Re: Way to keep your cool running a Raspberry Pi 4 (2019)

#93

Post by StillBored »

Spivak wrote: post #66
jstanley wrote: post #35

Earlier quoted context omitted.

This is basically an appeal to authority. You haven't explained what property of the Raspberry Pi 4 means that a tiny heatsink is sufficient. Why can't I just replace the words "raspberry pi 4" with anything else and conclude that I never need fans or large heatsinks?

Because you can see in the graphs that the bare pi doesn’t get that hot. If you allow just a bit more heat to escape you push the graph down to where the peak sits just below the throttling point. For home/hobby use this doesn’t matter too much but you typically want to run as hot as allowable. It’s a win-win since small heat sinks are cheap and don’t have any moving parts.

Running 32-bit raspbian... Try that with a 64-bit OS, running 64-bit compiles/etc.

I have a huge heatsink on mine (40mm cube), and even without the overclock it will crank up to 80C doing long running compiles. Running it at 80C for an hour or two, the temp of everything on the board starts to approach 80C. Touching the usb ports at that point will give you a surprise.

So, I added a small 20mm fan, and set the profile to kick on at 60C, which generally keeps the soc thermals in the 60-70C range. No throttling, and still no noise because with that large of a heatsink it doesn't take much air to cool it.

Add in a couple hundred Mhz of overclocking and that fan stays on pretty much all the time.

Re: Way to keep your cool running a Raspberry Pi 4 (2019)

#94

Post by StillBored »

jdsully wrote: post #33
larme wrote: post #28

Earlier quoted context omitted.

What if I want to use pi 4 as a building farm? Especially now with the 8gb version out, it seems to be suitable for building haskell programms

I use my pi 4 as part of a build farm with a 2cm tall passive heatsink. It never goes above 65c.

64-bit kernel, or 32-bit?

Re: Way to keep your cool running a Raspberry Pi 4 (2019)

#96

Post by sixothree »

tosh wrote: post #41

vertical orientation also seems to impact temperature """ Simply moving Raspberry Pi 4 into a vertical orientation has an immediate impact: the SoC idles around 2°C lower than the previous best and heats a lot more slowly – allowing it to run the synthetic workload for longer without throttling and maintain a dramatically improved average clock speed. There are several factors at work: having the components oriented…

This is a useful article. Thank you.
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