FastCGI module available in IIS 7.0 did not work when CPULimit for the application pool was enabled. This was because when CPULimit feature was enabled WAS uses job objects to track CPU usage of worker processes. WAS keeps a job object for each application pool and all worker processes which belong to that application pool are made part of that job object. FastCGI module uses job objects to make sure that there are no orphan child processes left when worker process goes away. Note that FastCGI requires a per process job object while WAS requires a per application pool job object. For this reason, it was not possible to make WAS take care of killing FastCGI child processes when worker process dies.