Hmm thanks for the post, Im looking into this and I my self have had really really irratic performance.
There are many posts on VBulletin 3.6.2 having performance problems and the common fix is to run the Repair and Optimise on the database tables. I did this and noticed an immediate improvement in stability. However im getting the same problems again now and performed the repair and optimise once more. IT came out Clean.. So will need to further research the problem.
The dedicated server is not even near half capacity so it cannot be a server side problem.. must some configuration problems with VB. Since im a VB noob would appreciate it if you have any pointers
