How to adjust an IIS application pool in Plesk?
How to protect the sites from each other so that one site cant affect performance/availability the other sites?
Go to Domains > example.com > Dedicated IIS Application Pool for Website.
Set Maximum CPU usage (%) limit.
Select Limit action that IIS performs when a worker process exceeds the configured maximum CPU usage.
Set Limit interval (minutes) to specify the reset period for monitoring of CPU usage on an application pool at option.
Note: Actual values depend on server configuration and can be based on previous performance monitoring results.