Does anyone have a good reference for how IIS manages memory? I understand it well enough, but I need something that amounts to "proof" for our customers. I've got general information from newsgroups and web sites, but nothing definitve. What I really need a some sort of benchmark.

Our customers seem to think a web server should act like a desktop application and free up memory when it's idle. We've tried explaining that web servers hold onto resources so they can be highly responsive. Our customers are worried that we still have memory leaks in our web apps that cause the memory to climb. This was true at one point because of a bug in a component, but that's been fixed. We also use automated tools to check for memory leaks, in addition to having a pretty good code review process.

Without a baseline reference to what normal IIS memory usage is, it's hard to make a strong case against perceived "memory leaks." So for now, we've had to write code to unload a web when it's idle, completely defeating all the optimization built into IIS. Any information would be appreciated. If you have web apps using server-side components in ASP pages, I'd be very interested in what you've experienced regarding memory usage on the server.