It looks like you are creating threads to perform expensive IO operations. To assemble a web page, this makes no sense. Each request should just use 1 thread. Adding threads will increase execution up to a point (and the increase will only be small), but its not scalable. It will take less traffic to use more resoures.

What you should be trying to do is something like the .Net model. 1 thread per request. You can speciify callbacks when performing expensive IO operations so that the current requesting thread is released and then continued after the IO operation.

This can signifigantly decrease the load on your thread pool and allow you to serve a signifigantly more requests. This is the kind of performance you want to concider. Less resources so that the app can do more (wich is incredebly important to web apps as they are multi-user).