Funny to consider that a VM running #Slackware 15 uses around 11% of host CPU, while the exact same VM (CPU / RAM / HDD / etc.) running #NetBSD 10.1 uses only 1.1%
I am now going to try and stop a few services under the Slackware VM to see if I can bring the CPU usage down. But I suspect the real culprit really is the kernel.