I'm afraid I can't be much help. There are several users - including myself - who are struggling with ArtRage and Sonoma.

Here are a few desperate suggestions:

1. Make sure all other graphic apps are shut down.
2. Make sure 'multithreading is toggled 'off'. <Edit><preferences><advanced preferences>
3. If you're using a tablet, make sure the drivers are up-to-date
4. Call a shaman and sacrifice a chicken (just kidding!)

Other than that I can offer nothing except sympathy :-(

Brett