F3 multi core performance not what it should be?

Is there something about the SpacemiT-K1 that would cause any problems when running multi-core tests? I’ve been seeing cases where testing that utilises >6 cores (Such as just using xz with either various -T parameters or running several in parallel) don’t always to show much inprovement above 6 cores, and even more frequently there is little difference going from utilising 7 to 8 cores.

Have others seen anything like that (so the first question is “is it just me?”). Similar behavior observed with both Armbian and Bianbu. Is there some quirk of the chip architecture that would explain this? I’ve not seen anything to suggest that the eight cores over the clusters are anything other than identical but if that’s not true let me know

The load on the machine from uptime/top is typically showing as about 2 when “idle”, with no processes using any significant CPU, which is a little odd but I have seen that on other SBCs before.