The Raspberry Pi 4 needs a fan • Hacker News Board

Re: The Raspberry Pi 4 needs a fan

#201

Post by FullyFunctional » Wed, Jul 17, 2019, 8:29 PM UTC

gadgetoid wrote: post #46

seanhandley wrote: post #3

Earlier quoted context omitted.

I tried a heatsink but it didn't really help unless I had a desk fan providing some air flow.

This pretty much lines up with my findings. I popped the pre-installed heat-spreader off and applied a heatsink with noctua thermal paste... basically no difference- step-by-step chaos here: https://twitter.com/Gadgetoid/status/1151442153584910337 Just adding a small fan (trying to avoid blowing our own trumpet too much here) absolutely demolishes the cooling performance of any reasonably-sized heatsink. Presumably t…

I appreciate you actually trying. A "negative" result is still valuable.

What I don't like about the article is that small fan have to spin fast (= noise) to generate enough flow. I'd much rather use a 80 mm fan, slowed way down, but I suppose I'd had to roll my own case for that. Better still, wait for someone to start offering this (or maybe this: http://blog.flirc.tv/index.php/2019/06/24/new-pi-4-cases/)

Re: The Raspberry Pi 4 needs a fan

#202

Post by newsreview1 » Wed, Jul 17, 2019, 8:31 PM UTC

The new Pi 4 looks amazing! It’s crazy to think the original only had a single-core processor, 256MB of RAM, and one USB slot.

Re: The Raspberry Pi 4 needs a fan

#203

Post by amelius » Wed, Jul 17, 2019, 8:36 PM UTC

pslam wrote: post #146

This article is actually describing how the Raspberry Pi 4 does NOT need a fan. This is not the 1990s. It is perfectly acceptable and even advantageous to design for a high peak:normal load ratio, with thermal throttling. In this case, it allows for a compact, cheap, fanless design for the vast majority of users. There is no evidence the heat dissipated will impact lifespan. It is common for the components picked out…

If you advertise a product with certain specs, and the user can only use the full capability during a fraction of the time, then that is misleading.

Re: The Raspberry Pi 4 needs a fan

#204

Post by ChuckMcM » Wed, Jul 17, 2019, 8:44 PM UTC

Apropos of the thread: https://www.seeedstudio.com/ICE-Tower-CPU-Cooling-Fan-for-Ra... (a fan for the CPU that is reminiscent of the first "big" Pentium fans). I asked on twitter if the RasPi had "jumped the shark" here, being sucked into territory it wasn't really designed for.

As someone who has lived through the microcomputer revolution it is amazing to see the "$100 desktop" at this point of history. If we arbitrarily pick 30 years as a delta (so 1989 vs 2019) and use BYTE[1] as a reference a 20MHz 80386 desktop with a 40MB hard drive was $2500 (as a clone, name brands were more).

An actually comparable computer (32 bit processor at 20MHz, 1MB RAM, 640x480 graphics, 40MB+ of storage (ignoring for the moment "protected mode") today can be built for less than $10.

That is a huge step function to try to absorb.

[1] https://archive.org/details/byte-magazine-1989-10/page/n347

Re: The Raspberry Pi 4 needs a fan

#205

Post by throw20102010 » Wed, Jul 17, 2019, 8:45 PM UTC

amelius wrote: post #203

pslam wrote: post #146

This article is actually describing how the Raspberry Pi 4 does NOT need a fan. This is not the 1990s. It is perfectly acceptable and even advantageous to design for a high peak:normal load ratio, with thermal throttling. In this case, it allows for a compact, cheap, fanless design for the vast majority of users. There is no evidence the heat dissipated will impact lifespan. It is common for the components picked out…

If you advertise a product with certain specs, and the user can only use the full capability during a fraction of the time, then that is misleading.

It might be misleading, but it's not uncommon. Apple MacBook Pros have thermal throttled at high loads for the past several years. It has throttled for so long that reviewers were surprised that the latest version seems to be using a decent thermal paste and throttles much less.

So if Apple got away with it for years on computers that mostly sold for over $2k, then I think the RPi foundation will probably get away with it on a $35 board.

Re: The Raspberry Pi 4 needs a fan

#206

Post by tracker1 » Wed, Jul 17, 2019, 8:46 PM UTC

geerlingguy wrote: post #170

ryanmercer wrote: post #148

Earlier quoted context omitted.

To add to this, I wonder if a properly designed case could create a chimney effect (not unlike the crossdraft kiln Primitive Tech made in his most recent video) where escape heat is drawing in cooler air in such a fashion as to be adequate enough fo the vast majority of applications. Not that fans need to be very loud, or even spin very fast for something of this size, I imagine relatively low RPMs (probably sub 100…

This is why I suggest in the video to just stick some ventilation holes in the top cover. Instead of the heat pooling in that area, it could escape, and there would be some natural convection—in through the gaps around the ports, out through the top. It wouldn't be as good as a fan, but definitely better than slapping a heat sink inside the case.

My plan was to just use a Dremel to notch some holes in the top of the case I ordered a kit with... I just ordered another case that has a fan and will try that... the new one will probably take over retro-gaming chores and I'll find something else for my 3B+ to do.

Re: The Raspberry Pi 4 needs a fan

#207

Post by unixhero » Wed, Jul 17, 2019, 8:47 PM UTC

codesushi42 wrote: post #193

pslam wrote: post #146

This article is actually describing how the Raspberry Pi 4 does NOT need a fan. This is not the 1990s. It is perfectly acceptable and even advantageous to design for a high peak:normal load ratio, with thermal throttling. In this case, it allows for a compact, cheap, fanless design for the vast majority of users. There is no evidence the heat dissipated will impact lifespan. It is common for the components picked out…

Fans fail too. The heat dissipated will probably shorten the lifetime of the board. At $35 who cares though? And you have more to worry about from the SD storage. The RPi needs an SSD. :)

Just get an Intel NUC

Re: The Raspberry Pi 4 needs a fan

#208

Post by Havoc » Wed, Jul 17, 2019, 8:51 PM UTC

My thinking has been more towards running with an oversized cooler.

e.g. I've got a tinkerboard which also tends to run hot & there simply adding a solid pound of copper did the trick.

Really not keen on having moving parts on my SBCs

Re: The Raspberry Pi 4 needs a fan

#209

Post by inetsee » Wed, Jul 17, 2019, 9:01 PM UTC

unixhero wrote: post #207

codesushi42 wrote: post #193

Earlier quoted context omitted.

Fans fail too. The heat dissipated will probably shorten the lifetime of the board. At $35 who cares though? And you have more to worry about from the SD storage. The RPi needs an SSD. :)

Just get an Intel NUC

A quick look at Newegg shows an Intel NUC that includes a CPU, memory, and an SSD at over $500. I don't think so.

Re: The Raspberry Pi 4 needs a fan

#210

Post by azernik » Wed, Jul 17, 2019, 9:03 PM UTC

DINKDINK wrote: post #137

JorgeGT wrote: post #116

Earlier quoted context omitted.

Yep, a lot of people nowadays is using IR cameras without any calibration or understanding of the physics behind the measurement. The truth is, the camera requires an emissivity coefficient to associate the received radiation with the emitter body temperature. There are tables for different types of materials, but the best is to calibrate against a surface thermocouple or similar. A corollary of this is, when you see…

>people nowadays is using IR cameras without any calibration or understanding of the physics behind the measurement The four factors are Emissivity (ε), Absorptivity (α), reflectivity (ρ) and transmissivity (t). Emissivity is only one facet. Ideal is high Emissivity and low reflectivity. https://en.wikipedia.org/wiki/Radiation_properties

Absorptivity is generally equal to emissivity (except for things that have wildly different emissivity in their blackbody IR spectrum vs the ambient IR spectrum).