It's All in the Process

Process Explorer is one of the staples of the hard-core Windows geek. It's a Task Manager replacement which does so much more; some would say it does too much. It's produced by Microsoft-acquired Sysinternals, which have been making some of the best in-depth system utilities for Windows even before Microsoft bought them out (years ago).
One of the best features in the new update is that you can now hover the mouse over any "svchost.exe" entry and get a whole list of services running under that process ("Group Policy", "Task Scheduler", etc.). That's very useful for trying to narrow down on what specific service is taking resources, even though a single svchost process can contain several services.