What version of kwin? The kwin developer fixed an important bug in 4.7.2 and right now, I unable to see CPU utilization go above 1%. Furthermore, I don't have Nepomuk installed.
FreeBSD uses KDE 4.6.5, so the fix from 4.7.2 is most likely not included (from what I know FreeBSD packages a mostly vanilla KDE, without any patches/backports). And Nepomuk is most likely active as it is enabled by default in KDE and Michael should not tweak default values without mentioning in the article.