[Alfa1]

The vbulletin support staff on vb.com have frequently stated that such large amounts of forum will cause performance issues, extreme server load and general forum slow down.

This is a database design limitation carried over from vb3. Once you get that many forums you start running into problems, particularly with forumjump, search and managing that many forums in the Admin CP/ forum manager.

The exact limit depends upon your server setup. A high end cluster will only hit performance issues at 1500 forums, while a low end server will hit problems somewhere below 1000 forums.

You can solve part of it by using Varnish & Sphynx.