When the Print Dialog is open, the messages Preprocessing Geometry and Processing Visible Edges are displayed for each of the attached rendered models and takes a long time to display every time you switch between models or change any settings in the Print Dialog. Turning on Rasterized and viewing the file in Wireframe display speeds this process up considerably, but the user might want to view the rendered version of the file.
To improve the performance of printing Rendered views of complex drawing models, either use Rasterize or change MicroStation Settings - Display Style to Smooth rather than Hidden Line and the surfaces are still displayed but Print will not perform the Preprocessing Geometry and Processing Visible Edges processes.