Raspberry Pi Compute Module 4 has PCIe support and new form factor

The Raspberry Pi organization releases the Compute Module 4 and the accompanying IO Board. There is a choice of 32 versions, with and without wireless connectivity, with 1 to 8 GB of Lpddr4 memory and with or without eMMC flash storage. Prices start at $ 25.

The Compute Module 4 has a new form factor. For the Compute Model 3, the Raspberry Pi organization still uses the DDR2 Sodimm standard, but the new model consists of a 55x40mm board with two 100pin connections at the bottom. Via these connectors, the Compute Module can be integrated into hardware, or connected to the IO Board that the Raspberry Pi organization releases itself.

The Compute Module 4 is basically the same as the Raspberry Pi 4 in terms of hardware. For example, the module has the same BCM2711-quadcore-soc, with Cortex-A72 cores at 1.5GHz. The board can decode H.265 videos in 4k resolution at 60fps and there is hardware support for encoding H.264 in 1080p30 and decoding in 1080p60. PCIe support is new. There is one lane available.

There are 32 versions of the Compute Module 4 available. Buyers can choose a version with or without wireless connectivity and each version is again available in versions with 1, 2, 4 or 8GB Lpddr4 memory. Each memory variant can be combined with 8, 16 or 32GB eMMC flash storage. The cheapest versions do not have flash storage. Prices start at $ 25 for the 1GB RAM version without Wi-Fi and flash storage. The most expensive model with 8GB ram, 32GB eMMC and WiFi costs $ 90.

The Compute Module 4 has no connections, but it does have the necessary interfaces on board. There is support for gigabit ethernet, two HDMI and PCI Express 2.0. Via the latter, users can, for example, use NVMe SSDs with an adapter, or add a USB 3.1 controller.

The optional IO Board for the Compute Module 4 costs $ 35 and has all the aforementioned connections. A MicroSD card can also be used in the IO Board, but that only works in combination with the Compute Module 4 versions that do not have eMMC storage. Furthermore, the Raspberry Pi organization is releasing an Antenna Kit. It contains a WiFi antenna that can be connected to the Compute Module 4 boards that support wireless connections.

Software developer Jeff Geerling has published a review of the Compute Module 4 and the IO Board. He describes, among other things, the operation of NVMe SSDs on the new hardware. These cannot yet be used as a boot drive and support for the NVMe protocol must first be activated in software.

According to Geerling, the Turing Pi company is working on a new version of its board that will allow the computing power of multiple Compute Modules to be combined. With the current version, seven copies of the Compute Module 3 can be pinned into the board. Due to the new form factor, a new design is required.

From left to right: Raspberry Pi Compute Module 4, 100pins connector from CM4, IO Board, Antenna Kit