ASP.Net memory management

I have some understanding of ASP.Net but I primarily deal with windows applications.

I have developed a large class which handles business logic. When in use it consumes 2 megs of memory. This DLL implements IDisposable and has a finalizer. (It has some unmanaged components)

When using the class in a Windows application the Framework correctly realises when the class is no longer referenced by anything and calls the finalizer and then removes the instance from memory.

However, on an ASP.Net webpage even after setting the pages reference to the object to nothing it does not call the finalizer, and remove the object from memory. It will stay in memory indefinately, the finalizer only gets called when I do an iisreset.

On my test environment I am running IIS 5.1. Is there something that I am missing? Do ASP.Net pages keep some hidden reference? The page I am testing it on has the reference as a private member.

Any help would be appreciated.

An ASP.NET application run continuously until the server is reset (shutdown or such), or maybe the last session has timed out(not sure bout last statement).

Its possible the .Net framework is caching the object, so its ready for immediate use.