I began adding new users to my site tonight, all as authors. Is there a limitation to the number of users or how quickly they are added, after adding the 50th user there seems to be a minute or two delay before wordpress will allow me to add the next user.
Limitations when adding new users
WordPress doesn’t have any real limitation to that although your
wp_userstable may not be optimized and the queries to it become slow. Try doing this:user_loginoruser_nicenameand play around until it speeds everything up a bitYou may also try disabling plugins one by one just in case there is a badly coded WP hook/action.
As a final solution, I would add a huge list of users directly through a SQL query, that way you can add thousands of them in less than a second.