If Windows Task manager shows excessive resource usage (CPU or memory, mostly) for an IIS 7 worker process (w3wp.exe), it’s helpful to identify which of your application pools consumes the resources. I haven’t found a way to accomplish this in IIS Manager so I proceeded like so:
At the command prompt:
net start WAS
Note: WAS is the Windows Process Activation Service (btw, pretty silly service name, as it’s nigh impossible to google for WAS).
Run appcmd list wp:
C:\Windows\system32>%windir%/system32/inetsrv/appcmd list wp
WP “5716″ (applicationPool:DefaultAppPool)
WP “968″ (applicationPool:MyOtherAppPool)
WP “5836″ (applicationPool:TheThirdAppPool)
The number in the results is the process ID in the results is the Windows process ID (PID).
Now in Windows Task Manager, after having enabled the PID column in View>Select Columns… you can identify the offending w3wp.exe by its PID.