fyi -APUG now running new dedicated search application.
Our performance issues of late (as far as I could trace) were related to our vBulletin search & search indexing not coping with our large volume of posts. I now have us running on a dedicated search & indexing application. This system is highly efficient, used by most if not all vBulletin "big board" owners. It removes vBulletin software from struggling to manage our data search & indexing. It was quite the nightmare to implement but we'll be far better for it. If you encounter search errors or issues please post here.