Receiving 503 errors - service unavailable. IIS (Application Pool) for Archer site crashes.
3rd party process causing out of memory exception.
CPU spikes in relation to the W3WP process.
Windows Event Viewer has "Warning" level event entries similar to:
Event Type: Warning
Event Source: W3SVC
Event Category: None
Event ID: 1011
A process serving application pool 'DefaultAppPool' suffered a fatal communication error with the World Wide Web Publishing Service. The process id was '1234'. The data field contains the error number.