I have a few applications that are desinged practically in the same way. I am using IIS as a web server.
One of the applications has a very strange problem. It would take much longer time to get data from the server than others. Here is a strange part:
If I add a user that runs Browser with the application in question to a local admin group on the web server then it works fast. Well, further investigation has unvealed that it's not data at all. It simply takes much more time for non local admins to get their requests to hit back-end module.