The RPi4 SoC has a busted PCIe controller (can't do 64-bit operations), the Rockchip one has a very small BAR size limit, so neither can run GPUs for example.

The RPi4 SoC has a busted PCIe controller (can't do 64-bit operations), the Rockchip one has a very small BAR size limit, so neither can run GPUs for example. The real ARM board options are SolidRun MACCHIATObin and SolidRun HoneyComb LX2K.