Raspberry Pi Compute Module 4 review: A building block for new devices Review

So you’ve got been experimenting with a Raspberry Pi four, and have occur up with a terrific strategy for a piece of Pi-controlled components. No-one’s accomplished it ahead of and it is really likely to be some thing the entire earth demands. But how are you likely to switch it into a solution? 

You could just get 1000’s of Pi 4s. Or you could sit down with the Raspberry Pi Foundation’s chip suppliers and a group of digital engineers and make your possess board absolutely from scratch. Alternatively, you could just take a shortcut and make your solution all around some thing intent-created for solution advancement.

That alternative is the Raspberry Pi Compute Module 4 (CM4). It has all the essential parts of a Raspberry Pi four on a solitary, a great deal scaled-down, board with a set of conventional interfaces that plug into a provider board with all the rest of the parts desired to make and run a gadget. Everything that goes into a total-blown Pi is on the compute module, all set for you to switch your components and computer software into a solution. 


The Raspberry Pi Compute Module four (CM4) has all the essential parts of a Raspberry Pi four on a small solitary board.

Pictures: Raspberry Pi Basis

Having began with the CM4

To make it much easier to get began with a CM4, the Raspberry Pi group has formulated a carrier board to aid with the upcoming stage of advancement, exposing all the CM4’s IO ports, including a PCIe connector. All you need to have is a CM4 and a electrical power provide and you might be all set to start off developing. I fitted mine into a professional case from Waveshare, which gave me obtain to all the gadget outputs (and with lots room to place a HAT inside the case if I needed) and included a admirer for cooling. 

I utilized a generic 12V electrical power provide as the CM4 doesn’t use the exact same USB-C electrical power connectors as the Pi four. As a substitute, it usually takes electrical power from its provider board, using every little thing from electrical power-above-Ethernet (PoE) to batteries and past. 


A set of conventional interfaces on the CM4 plug into a provider board with the rest of the parts desired to make and run a solution.  

Pictures: Raspberry Pi Basis  

Our test CM4 arrived with 8GB of memory and 32GB of onboard eMMC storage, jogging on a quad-main ARM Cortex-A72 processor. There are 32 diverse variations of the CM4, with diverse memory and storage configurations, so you can pick out a board that is correct for your venture. The increased-close CM4s, like our test gadget, are intended for compute-primarily based jobs, managing storage arrays or performing as IoT hubs for a selection of sensors. You can use the CM4’s PCIe interface to increase much more and faster storage, plugging in a M.two SSD or equivalent. 

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Other connectors on the IO board incorporate two screen and two camera connectors, as nicely as a total set of GPIO pins. You can find also Gigabit Ethernet with help for PoE. Wi-fi and Bluetooth antennas are created into the CM4 circuit board, while you may favor to use an external antenna. Just one massive change involving the Pi four and the CM4 is the absence of any USB three. ports. These are replaced by the CM4’s PCIe port, which can be utilized for any supported PCIe accent, including storage, networking, graphics, and USB three. boards. All you need to have is a Raspberry Pi port of any drivers. 

Putting in software 

Having an working program onto a CM4’s eMMC storage just isn’t as straightforward as plugging in a all set-formatted MicroSD card or a USB SSD (while all those possibilities are readily available if you favor). You are going to need to have to down load and set up a remote boot resource on a Laptop with the correct gadget drivers ahead of delivering an OS image to the CM4. 

It is really a very good strategy to use the IO board to configure your to start with CM4s, while if you might be in creation you can produce a tailor made OS via a focused gadget programmer. Put in the rpiboot tools on a Laptop and hook up the CM4 IO board by using a Micro-USB cable. Initially you need to have to in shape a jumper to disable eMMC boot, and as soon as that is in spot, electrical power up the CM4 IO board with a 12V PSU. Operate rpiboot to boot the CM4 above a USB cable from your host Laptop. 

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This will hook up the CM4 eMMC as external USB storage. From this point things are extremely common, as you use the Raspberry Pi imaging instruments to put in an working program. I installed Raspberry Pi OS, as this would let me place the CM4 via its paces. This took a small although, as it had to load above USB two.. The moment put in, I then had to edit the device’s config.txt to switch on USB two. help. This defaults to off to save electrical power, so duplicate the configuration specifics from the CM4 info sheet to switch it on and use your components with a mouse and keyboard. 


Raspberry Pi OS jogging on the Compute Module four.

Image: Simon Bisson / ZDNet

Utilizing the CM4 

The moment set up, a CM4 is like any other Raspberry Pi four. It runs the exact same working devices, and features the exact same instruments. That is the massive gain of the CM4: you can just take what you’ve got created on with the Raspberry Pi and convey it to new components. You can find no finding out curve for the computer software or for components, as the exact same GPIO pins are exposed via the CM4’s connectors. 

Efficiency is on a par with a conventional Raspberry Pi four. Utilizing the beta ARM make of Geekbench five.four, solitary main effectiveness arrived in at 181, with multi-main at 549. That is a little slower than our USB three. SSD Pi four, which helps make feeling as eMMC is fairly gradual (but faster than jogging from a MicroSD card). There is the alternative of overclocking in the program config, but we might propose fitting a admirer ahead of trying it out. 

The CM4 just isn’t only for industrial programs. Third-get together boards give the alternative of developing arrays of Raspberry Pis, in not extremely a great deal room, using a typical backplane to hook up your devices. Just one alternative is components like the upcoming Turing Pi two, featuring compact and potent compute devices created all around various CM4 modules. A Turing Pi two can be utilized as a Kubernetes program at the network edge, with 32GB of RAM and lots of SSD-primarily based storage. 


By supporting a large selection of 3rd-get together provider boards, the CM4 is becoming a generic compute factor for the IoT earth. The common Raspberry Pi may be a typical-intent gadget, but the Compute Module allows you concentrate on certain tasks, wrapping it in focused components. Do you want a Pi-hole privacy program as part of your household network? Why not locate a networking-focused Compute Module host and use it to make a tailor made router? Or potentially place just one in a mechanical keyboard to make your tailor made textual content editor for when you need to have to concentrate on composing? 

Treating a computer system as an factor of compute is a diverse way of pondering, but just one that is potentially superior suited for the earth of the World-wide-web of Items and the smart edge of a cloud-indigenous earth. With the CM4, the Raspberry Pi Basis is likely past checking out computing, to encouraging you locate new methods of building new things from what you’ve got acquired.  

It is really a massive stage to just take, but just one that fits in with the heritage of household computing in the United kingdom, pursuing on from what men and women did just after they’d expended their teenage several years with Sinclair Spectrums and BBC Micros. 

Who appreciates what Era Pi will make? You can find just one factor we can guess, even though: they’re going to be starting off with devices like the Compute Module four.


There are 32 diverse Compute Module four configurations starting off at £24/$twenty five for no on-board storage, 1GB of RAM and no wireless. The best configuration is 8GB RAM, 32GB eMMC and wireless for £85.40/$90.

The different Raspberry Pi Compute Module four IO Board fees £33.30/$35.

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