DAW seems sluggish and unstable when Duende is full. My host application doesn't show high CPU usage.
SSL says that in early releases of Duende, if all available DSP is being used on Duende, a high kernel load may be placed on your host CPU. This may not be reflected in your host app's system (CPU) usage meters.
Watch Apples Activity Monitor if a user is having a problem. Make sure no other applications are running to help reduce the load.