The Raspberry Pi 4 needs a fan • Hacker News Board

Re: The Raspberry Pi 4 needs a fan

#21

Post by teraflop » Wed, Jul 17, 2019, 3:03 PM UTC

LeonM wrote: post #6

So does the pi 3 if you stick it in a case, even with a heatsink. I was using a pi 3 with a heatsink in the official case to play a h265 movie (which will be software decoded on a pi3). After about 10 minutes I noticed it started dropping frames and it displayed the thermometer symbol in the top-right of the display. When I removed the top lid from the case, the temperature dropped enough for the thermometer icon to…

Yeah, thermal insulation behaves in much the same way as electrical insulation. If you put a conductor in series with a resistor, the conductor doesn't conduct all that well.

Re: The Raspberry Pi 4 needs a fan

#22

Post by adrianmonk » Wed, Jul 17, 2019, 3:05 PM UTC

> If you run computing hardware at its thermal capacity for long periods of time, this will cause more wear on the parts than if they are run well inside their limits.

So I have a moderately increased likelihood of, at some indefinite point in the future, having to spend a whole $35 to replace the Raspberry Pi. I can prevent this by spending extra money (and time) up front.

In some cases, it might be worth it. Maybe I'm using this Pi to control something, so downtime is bad. (But even then, fans have moving parts and a high failure rate, so plan to monitor the fan's condition and be prepared to replace it.)

In other cases, if the performance isn't important to you, it may make more sense to just accept a shorter lifespan. By the time it breaks, the next generation Pi may be out anyway. I don't love thinking of hardware as disposable, but at this price point, it may be smarter economically.

Re: The Raspberry Pi 4 needs a fan

#23

Post by Someone1234 » Wed, Jul 17, 2019, 3:05 PM UTC

reallydontask wrote: post #2

I'd guess that heatsink and a case with heatpipes would be sufficient for most, though perhaps not all, uses and silent, which for me is pretty important on a Raspberry Pi

That's what Apple used to do with their Macbooks. Heat pipes into the metal frame which conducts it over a larger surface area creating natural convections which carry the heat into the air.

The real downside is that mass plays a substantial role. Meaning thicker metal, larger cases, are better than thinner/smaller. Whereas a fan can accomplish similar results for less cost and space (but not passively).

If people don't think passive can work they need to check out Apple's recent Mac Pro that passively cools two Radeon Pro 580Xs. There's no limit, except cost.

Personally I still feel a combination of heat pipe, into heat sink, with a small progressive fan is the ultimate. If it is large enough the fan should stay off except under heavy load.

Re: The Raspberry Pi 4 needs a fan

#24

Post by the_angry_angel » Wed, Jul 17, 2019, 3:05 PM UTC

y04nn wrote: post #7

I installed libreelec on my Raspberry Pi 4 the first day I had it. The CPU immediately started (while playing 1080p video) to heat a lot to the point it stalled. Since I haded a motherboard chipset heatsink that I had laying around on the CPU it worked flowlessly. (I keep it without any case)

This was exactly my intended use case - as a gift for relatives - the problem I've had is that I need it enclosed to prevent tiny little fingers from getting hurt/destroying the thing. Tried soak testing it one night and experienced the same thing :/

Currently I'm hoping that I can modify the case this weekend to fulfill my needs.

As something intended to be used by kids to learn about computing I do wonder how many are going to get hurt fingers from the heat output by accidentally maxing the cpu and/or touching the USB ports, etc.

Re: The Raspberry Pi 4 needs a fan

#25

Post by spiderfarmer » Wed, Jul 17, 2019, 3:08 PM UTC

adrianmonk wrote: post #22

> If you run computing hardware at its thermal capacity for long periods of time, this will cause more wear on the parts than if they are run well inside their limits. So I have a moderately increased likelihood of, at some indefinite point in the future, having to spend a whole $35 to replace the Raspberry Pi. I can prevent this by spending extra money (and time) up front. In some cases, it might be worth it. Maybe…

I would accept the shorter lifespan just because of the fan noise. Small and cheap fans are very noticeable in otherwise quiet rooms. I'd hate it.

Re: The Raspberry Pi 4 needs a fan

#26

Post by vvanders » Wed, Jul 17, 2019, 3:10 PM UTC

malensek wrote: post #9

Even the previous-gen Pis would easily throttle under load without a heat sink (although usually installing a decent heat sink was enough to resolve the problem, assuming decent airflow). As the article notes, the heat was mainly from the SoC in the past. The Pi 4 is on a whole different level indeed. I imagine the logic here is the same as with many other Pi accessories: if you need it, you'll buy it or get it as pa…

Your phone will do this too, that's why sandwiching icepacks between your iPhone makes it do an iCloud backup faster.

Lots of vendors disable thermal limiting during benchmarks to get better numbers.

Re: The Raspberry Pi 4 needs a fan

#27

Post by TylerE » Wed, Jul 17, 2019, 3:12 PM UTC

teraflop wrote: post #21

LeonM wrote: post #6

So does the pi 3 if you stick it in a case, even with a heatsink. I was using a pi 3 with a heatsink in the official case to play a h265 movie (which will be software decoded on a pi3). After about 10 minutes I noticed it started dropping frames and it displayed the thermometer symbol in the top-right of the display. When I removed the top lid from the case, the temperature dropped enough for the thermometer icon to…

Yeah, thermal insulation behaves in much the same way as electrical insulation. If you put a conductor in series with a resistor, the conductor doesn't conduct all that well.

Seems like the winning solution would be to do as Apple does and make the case the heatsink. Aluminum is a pretty good thermal conductor, and at the very least it'd get you lots of surface area.

Re: The Raspberry Pi 4 needs a fan

#28

Post by geerlingguy » Wed, Jul 17, 2019, 3:14 PM UTC

BaconJuice wrote: post #20

Just a bit off-topic but what are you guys doing that you need to do CPU throttling? I just got a Pi4 and wondering if I'm missing out on some cool projects I can do with it :)

The Pi 4 is the first generation that's actually not horrible at running Kubernetes, so I'm mostly having fun with that (ongoing saga at www.pidramble.com).

Re: The Raspberry Pi 4 needs a fan

#29

Post by junaru » Wed, Jul 17, 2019, 3:15 PM UTC

adrianmonk wrote: post #22

> If you run computing hardware at its thermal capacity for long periods of time, this will cause more wear on the parts than if they are run well inside their limits. So I have a moderately increased likelihood of, at some indefinite point in the future, having to spend a whole $35 to replace the Raspberry Pi. I can prevent this by spending extra money (and time) up front. In some cases, it might be worth it. Maybe…

> If you run computing hardware at its thermal capacity for long periods of time, this will cause more wear on the parts than if they are run well inside their limits.

How true is this actually? Personal anecdote is an I5-2500K overclocked to 4.6ghz with budget aftermarket cooler (its at 4.6ghz constantly regardless of load). It's been running 24/7 in my desktop since 2011.

When will it fail? I see these disclaimers all the time and they sound logical, but does anyone have some numbers on these fail rates under these 'prolonged extreme loads'?

Re: The Raspberry Pi 4 needs a fan

#30

Post by AnIdiotOnTheNet » Wed, Jul 17, 2019, 3:16 PM UTC

malensek wrote: post #9

Even the previous-gen Pis would easily throttle under load without a heat sink (although usually installing a decent heat sink was enough to resolve the problem, assuming decent airflow). As the article notes, the heat was mainly from the SoC in the past. The Pi 4 is on a whole different level indeed. I imagine the logic here is the same as with many other Pi accessories: if you need it, you'll buy it or get it as pa…

Yeah, I'm kinda wondering just what the Pi is supposed to be at this point. Is it still an inexpensive low power device for teaching basic computer science? Because it seems like it's more for making Kodi boxes or the worlds most powerful LED blinkers.