I just realized, that PT doesn't seem to take advantage of the available CPU power efficiently.
During an offline bounce the overall system CPU consumption didn't exceed 60%, while the bounce would have benefit from higher usage as it only went with 2.7x.
A video export with Adobe Premiere does a much better job in utilizing the CPU.
Anybody have an idea why PT leaves nearly half of the available power unused?
EDIT: Black row on top with white scribbles = system wide CPU usage