Thanks, guys... helpful comments, all (I am still hoping for RHARV to check in, since I know he is well-acquainted with Ozone).

So, as suggested, I went ahead and loaded up a fairly complex RB sequence, putting Ozone on 4-5 FX Inserts, then on Aux1 Insert, then on the Output Master audio. The CPU usage, with each addition, mounted up, eventually to over 90, where I started getting dropouts. Below about 85%, things seemed fine.

So then I started taking out Ozone iterations, and substituting PG FX for Ozone presets. Clearly, with each substitution, the CPU usage fell progressively, which indicates to me (I am not a puter guy) that Ozone Presets use a lot of resources. Maybe the individual Ozone FX use less if you don't use the Presets, as suggested by Matt, which I will have to check later.

Incidentally, I am running a Core 2 Quad CPU, @2.40, with 4.0 GB RAM, 64-bit OS.

Looks like this Ozone 5 is gonna be fun, used judiciously.

Brad -- My FAWM