After completing an SBS 2003 to SBS 2011 migration we are experiencing problems on the network. We are finding logins are very slow in the morning. It can take up to 60 seconds for a user to login to the domain. I've seen DNS cause this problem but in this case DNS seems to be working fine. This SBS server is the only DNS server on the network and all clients are pointing to this DNS server and no others.
The second issue is that opening documents on the network is very slow as well. Probably due to the same issue.
The migration was a long and painful one with many obsticles. So far, we've been able to get everything sorted. But at this point we can't pinpoint this particular problem.
Any help is appreciated.