Controls in this rollout affect the operation of the mental ray renderer with respect to translation of the scene to the format the renderer requires. They also let you save the translated scene to an , which you can then use with a standalone renderer. The translated output uses the mental ray version 3 (mi3) format. The translator does not support mental ray version 1 (mi1).
The tools on the Diagnostics rollout can help you understand why the mental ray renderer is behaving in a certain way. The Sampling Rate tool, in particular, can help explain the renderer's performance.
Controls on this rollout are for setting up and managed distributed bucket rendering. With distributed rendering, multiple networked systems can all work on a mental ray rendering. Buckets are assigned to systems as they become available.