We don’t know yet which ARM SoC Radxa is talking about here but the "north bridge" in this picture is RTL9151AS:
➡️ 1x 2.5GbE
➡️ 7x USB ports (up to 10Gbps)
➡️ 4x SATA 6 Gbps
⬇️
Through one PCIe Gen 4x1 connection
With realtek's new "little north bridge" chip and low power Arm SoC, we can finally build compact Quad SATA NAS.