Subject: Raspberry Pi Compute Module 4 has been released

Specs:

Broadcom BCM2711 quad-core Cortex-A72 (ARM v8) 64-bit SoC @ 1.5GHz H.265 (HEVC) (up to 4Kp60 decode), H.264 (up to 1080p60 decode, 1080p30 encode) OpenGL ES 3.0 graphics Options for 1GB, 2GB, 4GB or 8GB LPDDR4-3200 SDRAM (depending on variant) Options for 0GB ("Lite"), 8GB, 16GB or 32GB eMMC Flash memory (depending on variant) Option for fully certified radio module:

2.4 GHz, 5.0 GHz IEEE 802.11 b/g/n/ac wireless; Bluetooth 5.0, BLE; On-board electronic switch to select either external or PCB trace antenna

More info:

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pi-cm4001000

Reply to
Faux Dameron
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Thanks for posting, it wasn't clear that they were going to do a CM version of the Pi4 when I looked into it a while ago. Interesting change in design.

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Reply to
Computer Nerd Kev

variant=raspberry-

I wonder how close in size that it to a mini-ITX motherboard and, if similar, do it's hold-downs match the mounting lugs in a mini-ITX case.

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Martin    | martin at 
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Reply to
Martin Gregorie

It is a great deal smaller than a mini-ITX motherboard at 55mmx40mm. You could pack a pretty large cluster of them in a mini-ITX case with a little ingenuity and a good fan.

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Steve O'Hara-Smith                          |   Directable Mirror Arrays 
C:\>WIN                                     | A better way to focus the sun 
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Reply to
Ahem A Rivet's Shot

CM4 is 55x40mm miniITX is 170x170mm

Or were you thinking of PC/104? Either way you'd only be able to use one mounting hole

Reply to
Andy Burns

In fact that is precisely what TuringPi does (aims to do). For now their ingenuity stops at 4, though:

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It seems to be an evolution of their V1 solution for the CM3 in SO-DIMM form where they managed to get seven on the mainboard, now with four CM4's on SO-DIMM-like adapter boards. Probably room for improvement.

Reply to
A. Dumas

Is that just intended as a "fun" project?

If so, then fine, have fun; but if not, I can't see a four x CM4 cluster being faster or cheaper than a workaday PC, even Oracle's one thousand x Pi3 cluster seems kinda pointless ...

Reply to
Andy Burns

Hmm rows of three mounted vertically, probably need about a 2cm pitch (height isn't specified) so a mini-ITX board with 24 compute modules could probably be built. The case would probably need to be mostly fan.

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Steve O'Hara-Smith                          |   Directable Mirror Arrays 
C:\>WIN                                     | A better way to focus the sun 
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Reply to
Ahem A Rivet's Shot

In many such clusters, having multiple nodes is the whole point. They're good for prototyping platformss like Kubernetes, which in production might have dozens or hundreds of servers in a datacentre. A Pi cluster makes that cheap enough to have that a whole cloud on your desk. You can then test the cloud features, like load balancing and resiliency (pull the plug on a Pi and check it fails over correctly). When you're done, deploy your app to the production datacentre (at the cost of $100 per hour or whatever).

Another use case is where you might end up running a pile of VMs on a PC - it can end up more efficient to run one task per Pi instead.

Theo

Reply to
Theo

The connectors are on the bottom, though, not on the side like with the SODIMM-like CM3, so you'd need some sort of adapter board which adds to the height, plus room for up to 200 connections for each CM4. Well, I haven't counted the actual number of signals... From the RPi blog: "two high-density perpendicular connectors (one for power and low-speed interfaces, and one for high-speed interfaces)" and from the datasheet: "The electrical interface of the CM4 is via two 100-pin high density connectors" and "The Module is 4.7 mm deep, but when connected the height will be 5.078 or 6.578 mm depending on the stacking height chosen." It also lists the complete pin-out:

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Reply to
A. Dumas

Thanks - I've been thinking on and off about using mini-ITX-type cases to house much smaller servers and more power-efficient desktop stuff rather than the big old whitebox dual-Athlon thats my current house server. The TuringPi setup is interesting, but very much overkill for what I need if/ when the dual Athlon goes bang.

Currently it looks like a single RPi 4 or a plain mini-ITX system would fit my requirements rather better.

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Martin    | martin at 
Gregorie  | gregorie dot org
Reply to
Martin Gregorie

OK so 2cm pitch should work - that motherboard is going to need a lot of layers though :)

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Steve O'Hara-Smith                          |   Directable Mirror Arrays 
C:\>WIN                                     | A better way to focus the sun 
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Reply to
Ahem A Rivet's Shot

Gives a whole new meaning to "box fan" ...

Buy six, make a box out of them!

Added points if the thing can levitate and move around.

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Mike Brown: mjb[-at-]signal11.org.uk  |    http://www.signal11.org.uk
Reply to
Mike

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