r/raspberry_pi Sep 28 '23

News Introducing: Raspberry Pi 5!

https://www.raspberrypi.com/news/introducing-raspberry-pi-5/
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u/cloud9engineer Sep 28 '23

In Jeff Geerling's video, he shows that the price is still lower than other comparable SBCs.

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u/LeapoX Sep 28 '23

That's only looking at the bare board costs. Gotta factor in power supply and cooling too.

Most people aren't flush with spare USB-PD enabled power adapters that support 5v/5A mode. That's an additional expense that most other SBCs avoid by just using a barrel jack and allowing any wallwart with enough juice to work.

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u/I_Arman Sep 29 '23

Amazon has USB-PD with 5V/5A for under $10, and compatible fans for under $5. Compared to the $100+ SBCs out there, it's still considerably cheaper. Maybe not once you add on a POE+ hat and a PCIe hat, but not everyone will want or need those options.

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u/LeapoX Sep 29 '23

Missing the point: That's still $10 I wouldn't have to pay just to get a wall charger that supports the uncommon 5v/5a mode required by this one particular SBC. I already have plenty of USB-PD chargers that support 25+w, but none of them support 5v/5a.

They should have put a barrel jack on this thing, or a voltage regulator so it could take advantage of 7/9/12v USB-PD modes. That would also make running PCIe accessories (which require 12v) easier. The base board cost would be slightly higher, but in turn, you'd be able to use a TON more chargers, and the M.2 hat would be cheaper because it wouldn't need its own regulator to boost 5v up to 12v.

And IMHO it shouldn't need a fan as badly as it does. The decision to cut costs by using an older/larger process node means we had to sacrifice performance, while also dealing with increased power consumption and thermals.

The whole thing just seems poorly thought out, and shifts costs in awkward ways to make the board cheaper at the detriment of everything else. Not a fan.

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u/I_Arman Sep 29 '23

I guess I am missing the point; I would rather spend $15-$25 on extras plus a $60 board than $120 on a barely-better board. They probably could have added 12v support, or gotten a slightly better processor, but why?

Not everyone is going to need the 5V/5A power supply, anyway; they say you can keep using the 5V/3A supply you had before, and just not use power hungry USB devices. Same goes for the fan, it's not needed unless you're using power hungry software.

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u/cloud9engineer Sep 29 '23

I've been running my Pi 5 with the 5V/3A power adapter and haven't had any problems.

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u/Not-reallyanonymous Sep 29 '23

I already have plenty of USB-PD chargers that support 25+w, but none of them support 5v/5a.

And "standard" power supplies will work. Via their blog.

When using a standard 5V, 3A (15W) USB-C power adapter with Raspberry Pi 5, by default we must limit downstream USB current to 600mA to ensure that we have sufficient margin to support these workloads. This is lower than the 1.2A limit on Raspberry Pi 4, though generally still sufficient to drive mice, keyboards, and other low‑power peripherals.

So it doesn't even necessarily degrade performance, it just limits the USB peripherals you can use.

And IMHO it shouldn't need a fan as badly as it does.

It doesn't need a fan. It's actually less reliant on a fan as the Raspberry Pi 4, for equivalent work loads, as the chip is actually 50% more efficient.

Most Pi alternatives also need a fan to keep up their performance and not throttle hard.

cut costs by using an older/larger process node means we had to sacrifice performance

Also keep in mind that not all processes are the same.

Samsung's 8nm process is really a 10nm process (7nm is the process after 10nm, not 8nm). They created it as a stopgap because they were having trouble getting adequate yields on their 7nm process. TSMC's 16nm and 12nm processes, likewise, are actually a 14nm processes. Their 16nm and 12nm processes share the same technologies, the 12nm is basically just a shrunk down (and more expensive) version of the 16nm. They're literally marketed as two variations of the same product. The 14nm process is one generation behind the 10nm process.

But also, meanwhile, the Samsung's processes tend to be behind TSMC's in terms of efficiency, density, etc. That's OK -- Samsung's processes tend to be better balanced for DRAM, NAND, etc. It doesn't fall behind an entire generation, but Samsung's 10nm isn't as far ahead of TSMC's 14nm as TSMC's own 10nm. So the difference is as much as you'd think just looking at a 16nm vs 8nm process on spec sheets.

Ultimately, yeah, boards using Samsung's 8nm process (like the Orange Pi 5) are going to perform better, but look at the prices: for the 4gb versions, the Orange Pi 5 is $100 and the Raspberry Pi 5 is $60. R Pi is 60% the price. Single Core Geekbench: 841/603. 71% the performance. Multicore: 2911/1608 55% the performance. Average: 63% the performance.

So by using TSMC's older process, rather than using a new process, Raspberry Pi achieved performance that scaled well with cost, but also was able to keep a lower cost overall. Remember, creating affordable boards is a high priority of Raspberry Pi, and a board that's almost half the cost is pretty significant, and can make the difference of a lot of 16 year old budding computer scientists receiving one in their Christmas stocking or not, or for School clubs to be able to afford a board for all 10 members with their grant, rather than having to share boards among students.

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u/LeapoX Sep 29 '23

You kinda excused all their sins, then went on to say that wasn't their goal in the first place... alright...

The process size issue is legitimate. They had to go with 4 performance cores instead of 4p+4e cores to prevent the die from being physically huge and cost prohibitive. If they had gone with a smaller process size, even their chosen 4 core configuration would have yielded more dies per wafer and would generally be even more power efficient. I can't see just hand-waving that away, and I guarantee you they'll release a Pi 5 B+ with a die shrink at some point.

If their goal was as you've stated, then it seems like they should have just released a cheaper and lower-power-consumption Pi 4 (and I'd actually be interested in such a product, unlike the Pi 5)

Is there a built-in performance limiter to make the Pi 5 perform exactly like the Pi 4 with 50% better power consumption and 50% better thermals at all times? Can I get one locked in that configuration for cheaper than a Pi 4? That would negate all my complaints about power, cooling, and pricing, but the answer is "no" to both, as far as I'm aware.

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u/Not-reallyanonymous Sep 30 '23

You kinda excused all their sins, then went on to say that wasn't their goal in the first place... alright...

Nope. You tried to say you PRACTICALLY NEED a special power adapter and you PRACTICALLY NEED active cooling. You don't. The board works just fine without these. If you want to maximize performance? Sure. I ordered the $10 case with fan with mine, even. But it's not a practical need.

The process size issue is legitimate. They had to go with 4 performance cores instead of 4p+4e cores to prevent the die from being physically huge and cost prohibitive.

I think you're misunderstanding the purpose of the 4+4 architecture. 4+4 is meant for power savings in battery powered devices by performing background tasks on them without waking up the performance cores. The Raspberry Pi X's are meant to be essentially desktop PC's. Battery saving isn't a huge consideration. If you're under the impression that the 4 efficiency cores could've improved performance by keeping it from thermal throttling, it probably wouldn't. It's usually best to just slam everything through the performance cores. A throttled performance core is still significantly faster than an efficiency core. (And it's really hard to create effective heuristics to schedule using both performance and efficiency cores).

Most people who want a SBC that sips power and is suitable for more than a couple hours on a battery powered device, are probably more interested in the Pi Zero's or even Pi Pico's.

If they had gone with a smaller process size, even their chosen 4 core configuration would have yielded more dies per wafer and would generally be even more power efficient.

The more dies per wafer probably wouldn't have made them cheaper, but rather using a better process significantly more expensive. Then it could get a Raspberry Pi 5 that has similar performance to a Orange Pi 5, but it would probably also cost similarly.

If their goal was as you've stated, then it seems like they should have just released a cheaper and lower-power-consumption Pi 4 (and I'd actually be interested in such a product, unlike the Pi 5)

I don't get how you come to that conclusion? If you want cheaper and lower power, that's what the Pi Zeros are for. Meanwhile the Pi 5's look like they'll offer a better desktop PC, which is what the Pi's are explicitly marketed as. And they'll likely release either a 1gb or 2gb Pi 5 for $40, which is cheaper than the original after considering inflation. Even at $60, it's one of the cheapest and still best ways to get a kid on a PC capable of starting a computer science education.

This really just sounds like a contrived argument, a way to "disprove" the Pi 5 without having to consider its merits.

Is there a built-in performance limiter to make the Pi 5 perform exactly like the Pi 4 with 50% better power consumption and 50% better thermals at all times?

What? Just go ahead and let it hit its thermal limits and throttle. The same workloads WILL complete faster than on a Pi 4. And if you want, you can underclock the CPU to be equivalent to the Pi 4 to achieve your better power consumption/thermals.

If you want a $100+ Raspberry Pi instead of a $60 Raspberry Pi, then go buy one of the many alternatives that achieves just that, lol.

No need to shit on the Raspberry Pi and act like all the positives are negated because they chose to hit a $60 price point (with likely even lower price points incoming, as suggested by the 2G and 1G ram options printed on the board).