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The Raspberry Pi 4 needs a fan

jeffgeerling.com

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Re: The Raspberry Pi 4 needs a fan

#101

Post by jrockway »

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 think if you focus too much on "$35" you will be very disappointed with the rpi. You need a power supply, that's $10. You need an SD card, that's $10. You need a case, that's $10. You need a micro HDMI to HDMI cable or two, that's $10. You need a fan, that's $10.

If you mentally decide "the Raspberry Pi is a $100 computer all-in" you will be much happier. You won't buy one to sit in a drawer (as many on HN have complained about), and you won't try to use a USB charger from your phone from 1992 and that SD card you got with your sandwich at IKEA and be disappointed that it's not very reliable.

Re: The Raspberry Pi 4 needs a fan

#102

Post by the_angry_angel »

krisrm wrote: post #98
the_angry_angel wrote: post #24

Earlier quoted context omitted.

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…

> 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. Sounds like one of the unexpected lessons will be heat dissipation :) Probably outside of the realm of weekend hacking, but I wonder if something like this would work for you: https://flirc.tv/more/raspberry-pi-4-…

Hadn't come across the case. I'll give it a go if my DIY attempts dont work (or are crap) :D

Re: The Raspberry Pi 4 needs a fan

#103

Post by delinka »

book-mind wrote: post #62
gadgetoid wrote: post #52

Earlier quoted context omitted.

There's a better image here- https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi...

That image is still highly misleading, you can see from the overlayed optical image that the CPU is not coated. Ideally you'd want to coat any metal surface with black epoxy, and set the IR camera Emissivity Coefficient to 0.9 (the coefficient for black epoxy).

Why would the overlay need to be with the board that had a coating? Buy two boards, cover the parts on one board that are silver, shoot IR. Use second board for visible wavelength photo, combine for a beautiful overlay result.

Re: The Raspberry Pi 4 needs a fan

#104

Post by hinkley »

kees99 wrote: post #44

Quote: the metal casing helps spread that heat around It does, to a degree. But that is absolutely not what we are seeing in that IR picture. Shiny bare metal is a mirror at the wavelengths that thermal camera uses. So what you see on thermal image where wifi-module shield and CPU are is reflection of ambient (room) where this picture was taken. Try waving your hand around, you'll see it reflecting there too. To meas…

To what degree does scanning it in a cold room help?

Re: The Raspberry Pi 4 needs a fan

#105

Post by jrockway »

HeWhoLurksLate wrote: post #43
junaru wrote: post #29

Earlier quoted context omitted.

> 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…

I've been running a I7-6700K on a 120mm AIO radiator for three years. It gets loud, but it also smashes my OC results. Personally, my biggest worry is the pump failing, and not the fans.

I used AIO for many computers, but every single system failed. It was the pump every time.

I switched to a Noctua passive cooler that I've used throughout motherboard generations (Noctua always releases a cheap kit to attach it to the latest socket type) and it has never been a problem. Thermals aren't a lot worse; I used it on 200W TDP 10 core SKUs, and on normal consumer chips. It has never let me down. AIO seems like a total waste to me; lots of moving parts to die on Saturday morning and make your computer unusable all weekend.

Re: The Raspberry Pi 4 needs a fan

#107

Post by dbg31415 »

robocat wrote: post #77
seanhandley wrote: post #56

Earlier quoted context omitted.

SD cards have a limited number of writes so if you have the OS constantly writing to it then eventually it sets itself read-only. You can mitigate this somewhat with https://github.com/azlux/log2ram With some finagling you can get them to boot an OS from an external disk then your SD card can just hold a read-only boot loader.

Heat causes flash memory to fail faster. I couldn't find a good source that quantifies the effect, but this mentions it: https://www.atpinc.com/blog/ssd-data-retention-temperature-t...

What I saw is that half the time the card was still good, if I put it into another RPi, and half the time the card and the reader were both shot.

Re: The Raspberry Pi 4 needs a fan

#108

Post by naikrovek »

kees99 wrote: post #100
geerlingguy wrote: post #55

Earlier quoted context omitted.

True, I worded it a bit wrong. But the metal case is a huge improvement over the plastic die package on the Pi 3 B and earlier—a heat sink helps a little but you don't yet _need_ one if you use a fan, since the metal is much better at dispersing the heat.

Indeed - there is enough aluminum/copper in the SoC's metal lid and PCB's inner (ground/power) layers, that the whole thing is effectively a 2-3 square-inch heat-sink. Eben himself has been talking about this technique around the time RPi3+ was released. And your point here is completely understandable too - there is a kinda-heatsink there already. Just add a fan, and we're good. My point is - seeing a large black ho…

How does it radiate enough heat with so little surface area (in comparison to an extruded aluminum heat sink with fins?)

Re: The Raspberry Pi 4 needs a fan

#109

Post by pas »

spiderfarmer wrote: post #25
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.

Big passive heatsink is not an option?

Re: The Raspberry Pi 4 needs a fan

#110

Post by whiskers »

Rychard wrote: post #94
whiskers wrote: post #75

Earlier quoted context omitted.

@mindcrime - I can't reply to you due to max depth. The current version doesn't, we're having a new, custom, fan made with an RPM feedback line for a future model but it'll be a couple of months yet.

If you click on the time above the post, it'll take you to a page where you can type a reply.

Much obliged!
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