[jeffgrant]

I'd also check your DB connection pool... see how those connections are being utilized. They can act the same way as web server threads/handlers, and can cause queuing from the app server. You could have X available DB connections, but X+1 requests from the app server, for instance.

It can be a fine line bumping up the available DB connections to provide enough to serve the app server without configuring so many that you get diminishing returns from the management of those connections/threads.

Not really sure of your technical stack, or the specifics of the configuration, but if you want to PM me I can offer some deeper advice on how to monitor and tune that stuff, if you want.

(I design and implement global online video game systems that handle 30+ million concurrent users, and specialize in tuning said systems... needless to say I've got a bit of experience doing this kind of stuff)