Is there an upper limit for users in WP?
Right now I use a single WP table to feed several sites. We have about 72K users and I have started noticing that to see the "Users" page it takes about 30 seconds on our otherwise pretty fast server. Are there any scalability issues I should worry about and anything I can do to get the user functions working quicker?
Extra Info: The user table is added to each night using employee data. There is nothing writing to the user table. We do allow users to edit some extra fields that get put into the metauser table. However there is no sign-up or registration. All of the sites simply define the user/meta tables in the config.