But the CPU usage is very high, up to 40% on my
moderately fast laptop
(i5-3230M CPU) for a single instance, regardless of the version.
Is this while you're playing notes? What is polyphony set to?
The cpu usage will scale with how many voices you are playing.
The UI also is a bit CPU hungry at the moment. Drawing all those arcs for
the modulation take a lot it seems..