If I return Mulab back to "default" OR turn off the Piano's multi-core support, things are back to normal, CPU usage is normal, birds are singing, etc.
I like to set my audio to 3 of 4 "cores" on my i5 dual-core just to have a little extra headroom as my CPU usage can get up there before I start printing VST audio for mixdown.
Has anyone else seen this or found this happening with other VSTs? This issue is no big deal, but was rather disturbing when it first popped up.
