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Comment by varispeed | Hacker News Reader

Missing opportunity to release 16GB version or at very least give specs of the memory so someone could swap chips.

> Missing opportunity to release 16GB version (...)

This seems to defeat the whole purpose of a Raspberry Pi: cheap, almost disposable computer to tinker around with.

A 8GB RPi4 board is already more expensive than some used desktop computers, and until recently some major hardware manufacturers (ahem apple) were still selling high-end laptops with less than 16GB of RAM.

I understand asking for features such as PoE and SATA support, but 16GB of RAM feels like an attempt to make the RPi something that's not supposed to be.

Also, 16GB LPDDR4x modules are crazy expensive right now, from what I've heard.

They didn't have the 8GB Pi 4 for the first year of launch either. I think it was Jeff G who said they were planning on a 16 GB release down the road.

Yeah https://youtu.be/nBtOEmUqASQ around 3:00

But in this interview https://youtu.be/vXYzJ1os4NA at 11:50 Eben says that the chipset does not support 16 GB.

Maybe it'll need a slightly upgraded broadcom soc like they did with the 8gb model of the Pi 4, or as a Pi 5+ variant

There are already tons of higher-RAM SBC options - check out PandaBoard.

They're awesome for prototyping, but there are so many places a Pi isn't the right fit or scale. They're common, not the only choice!

What do you need 16GB for that doesn't need a beefier CPU to match?

I've been running multiple 2GB Pi's and I can't think of any reason why I'd ever need more than 4GB. If I need that also want more IO (PCIe/NVME) and more CPU to make use of it.

AI models are a pain to getting running nearly as good on smaller amounts of RAM (if you can get them running at all) even though the compute itself plenty usable for many. If your use case is always going to be a home dns server or using a few GPIO pins then it doesn't really matter.

Any ideas on what it would take to accomplish this? Like how would the extra memory be allocated without a firmware change?

On the Pi 4, the BCM2711 supposedly supports 16 GiB (35-bit address space, with top half for peripherals and bottom half for SDRAM)[0 pg 5]. However, there seems to be some firmware limitation that limits you to 8 GiB of RAM, even if a 16 GiB chip is installed.[1] I would assume the BCM2712 would have the same address space (or bigger), and, as such, could support 16 GiB (or more) of RAM, but the firmware is written with the assumption that only 8 GiB of RAM will be installed.

The Pi firmware comes as a binary blob, but has there been any effort to reverse engineer it?

[0]: https://datasheets.raspberrypi.com/bcm2711/bcm2711-periphera...

[1]: https://www.youtube.com/watch?v=vtym0TAWNto

It's not a firmware problem, the memory controller only supports 17 bits for the rows.

So the hardware supports a memory map where 16 GiB of SDRAM could be present, but also limits itself to only 8 GiB in another area? Wow.

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