Server 2008, slow access to \\internal.domain

we have odd problem plaguing 1 of our on 50 servers.  whenever try log onto server taking on 10 minutes.  messages in event log 6005 , 6006 talking group policy timeout.  makes sense because after logged in, if type \\internal.domain can take between 9 , 15 minutes explorer display results.  specify subfolder \\internal.domain\sysvol , same results.

however, type server first dns on list, or pdc or name of server used authenticate , fast.

we can ping dns servers , running nslookup resolves quickly, less 1ms.

all servers have same dns priority list.

if log on using local administrator account fast, 10 seconds, suggests issue logon script or group policy has same script , group policies other servers on domain.

removing anti-virus did not speed logon.

disabling ipv6 did not speed logons.

any other suggestions?

\\internal.domain not real name.  referencing our internal active directory domain.  security reasons won't expose internal domain on public forum. 

we able figure out after extensive packet analysis.  piece of software installed on server reaching out domain controllers unacceptable amount of times due memory leak.  after removing software server magically came life , our world once again whole.

Windows Server  >  Network Infrastructure Servers