How to see which asp.net application in a pool is using the most memory

We have an application pool in IIS which a few applications belong to. According to Task Manager, this apppool is using over 4gb of memory, and I need to figure out which specific application is the cause of this.

Is there any way to get more information out?

You can use Performance Monitor and Debug Diag to generate dumps on high memory use conditions, including IIS memory usage. Performance Monitor will let you track Asp.NET memory used (there are several counters there), and Debug Diag will let you capture user dumps based on performance counters.

After Debug Diag processes a dump, it'll let you know which processes are using how much memory.

There's a longer article here. I hope that helps.

I might take a simpler approach and just put each site into it's own app pool and see which one is growing out of control.