Timbo: The numbers indicate that the server probably is overloaded at times. Some time it's the database backend that is slow, at other times it's the forum frontend that is slow.
E.g, my latest stats.
Generated in 12.99 seconds in which 0.013 seconds were spent on a total of 6 queries. Zlib compression disabled.
The database did its work fast, but the forum frontend which runs on the webserver (I suppose this forum runs on Apache and MySQL) used ~13 seconds to generate the page. Since it varies which subsystem is slow, I guess the server is bogged down doing something else. The question is what it is doing, as I dont see a influx of new users or increased activity.