Raspberry Pi 4

Hardware

- Video Core VI. Compatible with Video Core IV. New open source driver exists

- Standard XHCI USB controller, in addition to the embedded IP block that was in the Pi 1-3. The USB-A connectors are run by the XHCI block now, while the charging port is on the IP block. Previously they were all on the IP block.

- Network devices have a mac address mapping to https://maclookup.app/macaddress/DCA632 - the raspberry pi foundation's own block. Likely attached to pci-e as well.

- SD controller is now a SDHCI thing. Should work according to spec.

CPU is similar to the one in the Rpi3, except with the A53 cores replaced in-situ with A72. Same startup logic, same usage. Also limited to max 4 cores per chip by design.