I have a process holding 130MB of memory according to task manager, with only 11MB of live .NET objects according to dotTrace so I am wondering what\'s happening with the other
I use RedGate ANTS .NET Developer Bundle for these issues. Memory Profiler allows to identify memory leaks (like zombies objects) and to make snapshots of memory usage. You'll then be able to compare classes and instances between two snapshots. You can track down instance reference in a tree and easily view the top object who maintain the reference.
Besides, Performance Profiler provides code profiling to identify bottlenecks and CPU usage.
For years now, it helped us alot to find application problems within minutes.