[OpenWrt Wiki] PC Engines APU
https://openwrt.org/toh/pcengines/apu10.09.2021 · PC Engines APU APU system boards are designed and manufacturered by PC Engines. Boards are based on AMD Bobcat low consumption APUs. The boards and other components (enclosures, power supplies, wireless cards, CompactFlash cards, etc) are sold separately, although some retailers sell pre-build kits.
[OpenWrt Wiki] PC Engines APU 2
https://openwrt.org/toh/pcengines/apu2PC Engines APU 2 The APU2 is a small x86_64 single board computer. It will easily route/packet filter a one Gigabit WAN. IPsec/VPN may drop that number a wee bit, the CPU has AES-NI acceleration, use AES-GCM for performance. Tested wifi options include the PC Engines supplied
[OpenWrt Wiki] PC Engines APU 3
https://openwrt.org/toh/pcengines/apu310.09.2021 · PC Engines APU 3. The PC Engines APU3 boards are very similar to the APU2 boards, but they are designed to use two 3G / LTE modems, so the first two Mini PCIe slots have USB connection and are connected to the two SIM slots, and only the Mini pcie slot on the left has PCie interface. So in layman terms you can only install 3G/LTE/5G modem cards ...