[schapplm]

I have a database that have some tmdb entries. Most are tvdb/imdb does it affect having duplicates? I think it's slower progressing the watched but maybe it's in my head.
Is there a guide how to delete records/optimise the database?

The duplicates are not synchronized against each other, since the addon can not disguise if the tmdb and imdb entries are connected.
You can manually edit your database with the corresponding tools for mySQL or SQLite. But I do not think this is critical for the speed.