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Comment by geerlingguy | Hacker News Reader

There's a summary of all the new info along with a price list here: https://static.raspberrypi.org/files/product-briefs/2010016+... — $25 for the base model with 1GB of RAM, no WiFi/Bluetooth, and no eMMC, up to $90 for the high-end model with 8GB of RAM, WiFi/Bluetooth, and 32GB eMMC. All the models now have built-in gigabit ethernet, and a new board-to-board connector that means the CM4 is not compatible with the CM-CM3+ DIMM form factor.

See the announcement post for all the details, but I was lucky to be able to work with the CM4 for a few weeks, and I posted my impressions here: https://www.jeffgeerling.com/blog/2020/raspberry-pi-compute-...

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Thanks for the info! Looks like a really awesome little board that's going to allow all KINDS of interesting use cases. I really hope to see a new TuringPi cluster; doubly so with ESXi now being available!

One note about your article:

Due to the nature of PCIe, ANY GPU will happily run on the 1 lane presented here. The limitation will be data transfer, which primarily shows up in texture loading. Tom's Hardware did an article [0] a decade ago comparing lanes to performance. This is also why some x16 connectors will be listed as "electrically" x8; they only have 8 lanes exposed.

However, you will have issues with the power delivery; PCIe GPU's are allowed to pull up to 75 watts from the slot itself before going to direct connectors. There are ways to fix this; I ran a mPCIe (WiFi) to external PCIe adapter for a couple years on an old laptop with a GPU just fine.

Another use case (and likely more relevant) would be plugging in an HBA for a NAS. Upgrading the NIC to something multi-gig sounds interesting, but that PCIe x1 is not going to be any faster than the built-in GBe except in edge cases. I'm actually really curious to see what people do with this.

[0] https://www.tomshardware.com/reviews/pcie-geforce-gtx-480-x1...

Good to know; I'm honestly a little out of my element with GPUs because it's been a while since I've even thought much of them (I don't do much gaming and don't do many GPU-based workloads... the built in GPU is always fine for me!).

For the NIC, it's cool to see we'd be able to get two or maybe three gigabit interfaces on the same Pi, could be interesting for a variety of different networking devices, coupled with the faster SoC in the Pi 4.

I wanted to correct myself; with 500MBps bidirectional, that single PCIe lane could run a 5GbE at full saturation, or a 10GbE at a pretty solid fraction.

That changes the use case a bit; the Aquantia multi-gig cards have drivers for ESXi. You could then run an eMMC boot for the hypervisor and run everything via the higher speed adapter, saving the GbE for management/migration.

If only they had a eMMC socket instead - would cut down on production costs for the various models, help suppliers who would have less flavours to stock and add flexability to change the eMMC memory, or not.

32 flavours/models seems like choice-saturation. If they still make all 32 flavours a year from now, I'll be supprised.

> If they still make all 32 flavours a year from now, I'll be supprised.

They guarantee 7 years of availability for Compute Modules, including this one, so... prepare to be surprised.

They had plenty of time over the last 16 months since the launch of Pi 4 to decide how many SKUs to make for the Compute Module. This certainly wasn't done on a whim by some inexperienced team, which is what your post seems to imply. They've been doing this for years, and they realize the commitment they're making.

My postulation was based upon how they dropped the 1GB model of the Pi4 as it did not sell as well as the other models and was able to furfill it's role with lowering the price of the 2GB model, which happened about a year after the initial release.

It is perfectly viable for them to shift to socketed eMMC and still accommodate all available flavours. But then how they sell will set that and if out say 99% of sales are for only 5 models and a socketed eMMC consolidate the offerings whilst still providing exact compatibility with the initial guaranteed offerings, then I still would not rule out such a change a year on, once they see what flavours do sell.

That was the basis of my comment - nothing more, nothing less.

The embedded market isn't anything like the direct to consumer market. D2C allows for fine tuning like that in a way the embedded market simply doesn't.

If they change the product at all, downstream companies may have to get their products entirely re-certified, which can be an expensive and time consuming process. Those companies rely on having a stable supply of exactly the compute module that they designed their product around. Every detail matters.

These SKUs are fixed in stone. If they discontinue or modify them at all before the specified 7 year date, that would substantially damage their relationship with downstream companies. They have upheld their previous commitments, so I don't expect them to start breaking commitments now.

This looks pretty compelling - the only thing that bothers me a bit is that the eMMC seems to be soldered and not replaceable, giving it a much more limited lifespan, depending on how durable these eMMC modules are.

(Oh and BTW I had completely forgotten but cheers for the follow-up on TRIM/UASP for USB the other week :))

The "lite" versions don't have eMMC, so you would be free to put an SD card slot or similar on the carrier board.

Have you found reliability problems with eMMC? I've found it to be a lot more reliable than SD cards, faster too. Of course with 1 Gb networking you can move the heavy lifting storage for containers and VMs to something like Ceph and only use the eMMC for OS root disks and local storage.

For my Turing Pi, when it's delivered, I'm hoping to start with a small Kubernetes install for testing. Then when the TPi 2 is released next year, build a second one with CM4 modules for more involved Kubernetes testing/development while putting Ceph on the old one.

(To head off inevitable comment: no I'm not expecting this to perform well, and it's not for production work, it's purely for experimentation with clusters)

I've only tried one model so far (Samsung via Odroid) and yes, so far the reputation seems to hold that it's faster and more reliable than the supposedly best SD cards on the consumer market (and cheaper too!). But the underlying technology is the same and with several boards I'd expect to have at least some failures over the course of a year or so of continuous use.

The fact that they are soldered and not replaceable forces manufacturers to actually build quality storage. You can get away with bad SD cards but if the entire device is bricked then you will demand a complete replacement.

Thank you very much for your article, I read the hackaday one linked to on another thrread, twice, and could not understand what this stuff is about, while reading just a few lines of your impression I instantly got the essence.

Nice review, thanks. One thing in it that I believe is incorrect (or confusing) is PoE support: I don't believe it is built into the IO board but rather the board is compatible with the PoE hat.

Btw, thank you for your blog reviews and videos.

Compute Module 4 + IO Board looks like a winner setup for a small multimedia box

How does this handle the heat?

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