Windows Server 2008 / Active Directory 

Is there a way to measure the response time for queries going to AD? I have an application that checks to see if a user exists in AD and lately, this seems to be taking awhile (30-40 seconds). I'd like to know if the delay is on the AD server side or with the application itself. 

Would `csvde` be the best way of doing this? Or is there a special tool available for measuring AD query performance? I'm open to using third-party utilities if that would provide a more complete picture of what's going on.