If you're on an old BIOS revision for the APU (more than a couple of months old), try updating, they have enabled "core performance boost" which increases speed of a single core if the others are not under heavy load.
I haven't done network benchmarks but there is a noticable improvement in some other things (md5 -tt goes from 12 -> 9 seconds). To update BIOS from OpenBSD, pkg_add flashrom and download the BIOS version for your board (https://pcengines.github.io/). Go to serial console and reboot in single-user mode (boot -s), mount -a, and run "flashrom --programmer internal -w apuX_vXXX.rom". Then reboot back as normal. If you'd like to compare benchmarks, the feature can be toggled from the setup menu in BIOS. https://blog.3mdeb.com/2019/2019-02-14-enabling-cpb-on-pcengines-apu2/
