The Raspberry Pi 4 has just been released. This is the latest version of the Raspberry Pi and offers better CPU and memory than the Raspberry Pi 3, dual HDMI outputs, better USB and Ethernet performance. It will remain in production until January 2026.
There are three versions of Raspberry Pi 4 - one with 1 GB of RAM, one with 2 GB and one with 4 GB of RAM - available for $35, $45 and $55, respectively.
Improved CPU and graphics, more memory available
The CPU on the new and improved Raspberry Pi 4 is a significant upgrade. While the Raspberry Pi 3 featured a SoC Broadcom BCM2837 (4th ARM Cortex-A53 at 1.2 GHz), the new board has a SoC Broadcom BCM2711 (a 1.5 GHz Cortex-A72 quad-core). This provides desktop performance comparable to entry-level x86 systems.
Note, the new Raspberry Pi 4 features not one but two HDMI ports, albeit in a micro HDMI format. This allows support for dual display up to 4K60p. Graphics power includes H.265 4K60 decoding, H.264 1080p60 decoding, 1080p30 encoding, with openGL ES support, graphics 3.0. As with all Raspberry Pis, there is a composite video port built into the audio port. The 2-lane MIPI DSI display port and the 2-lane MiPI CSI camera port remain identical from the Raspberry Pi 3.
For anyone expecting a drop-in replacement of the Raspberry Pi 3, there is a very significant change: the power port is now USB Type-C.
Previously, and particularly with the release of the Raspberry Pi 3, there were noises from the Raspberry Pi foundation that no old USB power supply would be compatible. A standard USB power supply is guaranteed to provide 500 milliamps at 5V or 2.5 watts. Although this was sufficient for the first Raspberry Pi, energy budgets increased in the latter half of the decade. Now, a Raspberry Pi 3 will absorb more than 3 watts during startup. For any future generation of Raspberry Pi, this is unsustainable and there must be a power outlet that provides more energy.
USB-C serves precisely for this reason. With a USB-C power input, the Pi is not limited to the 500 mA limit of any old power adapter. It's a great design choice; If you were wondering why the original Raspberry Pi used a micro USB port for power, you could just tell because each phone used one for charging, so the micro USB power adapters were everywhere. Now, most flagship phones use USB-C chargers that provide more power and make up a great power adapter for any single-board computer. Of course, power can also be provided via the 5V guide on the 40-pin GPIO connector or via PoE with its PoE hat.
For years, the question has been about how to add a second high-resolution display to a Raspberry Pi. It would be possible to use the composite output with HDMI or a 666 VGA adapter. This requires more effort than connecting a second cable, so it has simply never been feasible. The Raspberry Pi 4 eliminates the large HDMI port for two micro HDMI ports, with support for two displays. Now, finally, the Pi is a real desktop replacement with native support for multiple monitors.
Faster USB and Ethernet
One of the big shortcomings of all Raspberry Pi so far has been bandwidth through Ethernet and USB ports. The real bandwidth of a USB port on a Raspberry Pi is about 250 Megabits per second, about half the maximum theoretical bandwidth of a 2.0 USB port. The maximum bandwidth of the Ethernet port was about 50 Megabits per second; better than 10 Megabits, but again about half the theoretical maximum of 100 Mbps.
The reason for this poor performance on USB and Ethernet ports was the combined controller. All Pis, except the Zero and now the Pi 4, was used in a combination of Ethernet and USB controllers, in the case of the Pi 3, a Microchip LAN7515 chip. This is a great way to connect some USB and Ethernet ports to a SoC, but real-world performance is always lower than theoretical ones.
Raspberry Pi 4 removes this combination of Ethernet and USB controllers. Now, finally, the Raspberry Pi has real Ethernet and USB ports. It has Gigabit Ethernet thanks to the Ethernet transceiver BCM54213 and USB 3.0 thanks to a VIA Lab VL805 chip that is connected directly to the PCI Express interface on the SoC Broadcom. The Pi 4 only has two USB 3.0 ports, but it should be enough for most use cases.
One of the biggest demands from the single-board computer community for any board is the addition of a SATA port. If you wanted to turn a Pi into a NAS, simply connect a hard drive to a SATA port. Although it is not a SATA port, the addition of USB 3.0 is huge; USB 3.0 offers almost the same bandwidth as a SATA port, and USB to SATA converters are cheap and already available.