Jim Roseberry
Open Task Manager... and go to the Performance tab.
That'll provide the exact CPU use... 
Yup I know that, I am just curious why it isn't working in Sonar, it works fine in X3.
EDIT: having only just got the card that can do 192k I had obviously never tested in x3 at the exact same settings so maybe it is the same in x3. Sorted now anyways.