The size of a database isn't really going to affect speed that much unless it is huge. In terms of site slowdowns and excess resouce usage, I'd be more concerned about the number of people accessing a site at once and how they are using the site. The database design for phpBB is good from what I remember, so accessing information stored in the DB is fast even when it is fairly large.



Lunarforums is a fairly active forum, but it isn't what I would call "huge".

Adrian, but you are on the enterprise plan though, right?

Thanks all. That's a relief.  

Typically my forum has about 30-50 users max at a time, I guess it's nothing.