The Nepomuk team has been working really hard to fix the problems with virtuoso consuming too much memory and often just going bat crazy. And now finally we've figured it out.
It wasn't the obvious solution, but we think it's going to work out very well. From now on virtuoso won't be shown in ksysguard.
Since we won't be able to see virtuoso using up our memory and CPU, it obviously won't be doing it. Now, I get that this logic is a little brain-dead, cause in Linux we have other ways of monitoring our processes as well.
Fortunately, Trueg is in the process in patching up top, and I'm going to be contacting the kernel people to see if we can remove virtuoso PID from /proc.
Problem solved! :)