Had the exactly same experience with 96kHz files and with other plugins as well (not Ozone). Noticed the same behavior with the cores. Never tried at 88.2kHz. 48kHz works perfect with a bunch of cpu hungry plugins but 96kHz is another story. Tried the buffer approach, no real improvement. I wish that I had a solution but we are in the same search. Sorry! Please let me know if you crack this one.