Consider a busy site with about 10,000 posts divided in 10 custom post types.
Custom taxonomies and custom fields are also used on all of them.
The main query was modified to include all these posts types everywhere, on index, archives, search, feeds.
Now, is there any performance hit caused by using custom post types versus regular ‘post’? Or it wouldn’t make no difference what types they are?
Read more here:: Is there any performance consideration when using Custom Post Types?