The U74-MC on that board’s JH7110 SoC is two 64-bit dual-issue cores at 1.5 GHz, so it’s fair to compare it with the four 64-bit dual-issue cores at 1.2 or 1.4 GHz on the RPi3’s Cortex-A53, or for that matter with something like a 1.0 to 1.4 GHz dual-socket Pentium III system from the early oughts (which would use the P6 32-bit dual-issue microarchitecture from the Pentium Pro).