The Raspberry Pi 4 needs a fan • Hacker News Board

Re: The Raspberry Pi 4 needs a fan

#251

Post by BubRoss » Thu, Jul 18, 2019, 3:34 AM 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.

That's basically modern CPUs for the modern consumer. Laptops often have cooling that can't keep up, same with intel NUCs. Same even with ryzens with integrated video cards. There are bios setting for relaxed thermal throttling that let it get hotter that are a huge boost to performance.

Re: The Raspberry Pi 4 needs a fan

#252

Post by DCoder » Thu, Jul 18, 2019, 3:42 AM UTC

sizzle wrote: post #232

CliffStoll wrote: post #195

Earlier quoted context omitted.

As a once-infrared-astronomer, I can certainly confirm your statement: Thermography is certainly not a straightforward "point-and-click" process. Six years of grad school...

Sounds like a cool profession, what are you up to nowadays?

I thought that username seemed familiar… [0]

[0]: https://en.wikipedia.org/wiki/Clifford_Stoll

Re: The Raspberry Pi 4 needs a fan

#253

Post by Rerarom » Thu, Jul 18, 2019, 4:43 AM UTC

DCoder wrote: post #252

sizzle wrote: post #232

Earlier quoted context omitted.

Sounds like a cool profession, what are you up to nowadays?

I thought that username seemed familiar… [0] [0]: https://en.wikipedia.org/wiki/Clifford_Stoll

Yup, if you look into his comment history he confirmed he's the same person

Re: The Raspberry Pi 4 needs a fan

#254

Post by arpa » Thu, Jul 18, 2019, 5:05 AM UTC

tagrun wrote: post #249

klickverbot wrote: post #247

Earlier quoted context omitted.

Physicist here too. What exactly do you disagree with? The parent comment is sound – thermal imaging cameras typically under-read on shiny metal surfaces. Their emissivity/absorptivity at relevant wavelengths is low, and reflectivity is high. Thus, their own Planck spectrum is (approximately) scaled down by their emissivity, and consequently the radiation in the measured MIR band is mostly what is reflected, which te…

Let me try again. Assistant Professor of Physics here (not a grad student). Yes, reflectance of room temperature aluminum at those wavelengths is pretty good (not true for all metals BTW). Yes, this usually makes it hard to distinguish thermal radiation and reflected radiation with metals. What are you trying to say though? That whatever comes off from a metal must always be a reflection coming from somewhere else? >…

Genuinely curious person here. What is the key reason to use photon size instead of wavelenght? To stress the quantifiableness of the radiation being capured by the thermal camera? To be honest it is the first time i've seen photon size semicasually mentioned in a conversation. Then again i only had physics in high school.

Re: The Raspberry Pi 4 needs a fan

#255

Post by pankajdoharey » Thu, Jul 18, 2019, 5:09 AM UTC

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…

Check the Ice Tower cooler for raspberry pi https://youtu.be/RyUXC3886Ic

Re: The Raspberry Pi 4 needs a fan

#256

Post by tuananh » Thu, Jul 18, 2019, 6:50 AM UTC

universenz wrote: post #228

inetsee wrote: post #209

Earlier quoted context omitted.

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.

I know right? People need to quit suggesting an Intel NUC as an alternative to $35 RPi.

adding up case, charger, a decent sd card and the pi is way above 35$

Re: The Raspberry Pi 4 needs a fan

#257

Post by bayesian_horse » Thu, Jul 18, 2019, 7:19 AM UTC

It already has plenty of fans, me being one of them.

Re: The Raspberry Pi 4 needs a fan

#258

Post by abainbridge » Thu, Jul 18, 2019, 7:26 AM UTC

tkiley wrote: post #248

pslam wrote: post #221

Earlier quoted context omitted.

Yes, wearout rate definitely depends on temperature, but without reference to any actual data, this is what I mean by "no evidence". Is it reducing 10 year lifespan to 9 years? 9.99 years? 5 years? Was it 50 year lifespan? It's pointless conjecture.

If the pi is designed to throttle at a temperature where its lifespan is reduced from 50 to 49 years, then it is throttling at a gratuitously low temperature that affects quite a few use cases. On the other hand, if it is designed to throttle at a temperature that materially reduces the lifespan, then it needs a fan to preserve its lifespan. Either way, the hardware is starkly suboptimal for a pretty large set of adv…

> If the pi is designed to throttle at a temperature where its lifespan is reduced from 50 to 49 years, then it is throttling at a gratuitously low temperature that affects quite a few use cases.

That's another claim that needs evidence. It seems possible to me that the thermal throttling is designed to prevent logic errors.

Re: The Raspberry Pi 4 needs a fan

#259

Post by Erlich_Bachman » Thu, Jul 18, 2019, 7:28 AM UTC

morganvachon wrote: post #219

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…

I'll respectfully disagree. Running my Pi 4 with no fan/heatsink reduces performance to an absolute crawl. It's on par with the desktop on the original Pi released in 2012, i.e. nigh unusable for anything beyond saying "yep, it boots to desktop". Thermal throttling effectively neuters the device. I have it in an open-air acrylic "sandwich" style case now, with the same Pi-Fan as the author, and it feels performant en…

He said "no fan", why do you include "no heatsink" into that? Those are very different things to operate without.

Re: The Raspberry Pi 4 needs a fan

#260

Post by paule89 » Thu, Jul 18, 2019, 7:30 AM UTC

I would love to have a case for the Pi which can utilise a normal Desktop Tower Cooler. Be it 80, 120mm size coolers. The larger the cooler the quieter it can be. (Looking at some nice Noctua fans) Alternatively the seedstudio one looks good but how loud is it really? https://www.seeedstudio.com/ICE-Tower-CPU-Cooling-Fan-for-Ra...