lsass and dfssvc

Hi,
I have a ProLiant ML350 G3 running Windows Server 2003 w/SP-1 as a Domain
Controller. I have a share setup on the server ... when clients access the
share they notice a delay on access and browsing and I log high cpu usage by
the dfssvc.exe and lsass.exe processes on the server. If one persone clicks
on the share .. the server CPU will jumped to 60% and stay for a moment as
the share is being displayed on the clients computer. Any ideas??? No other
processes seem to be interferring ... moving large files from the server
across the network doesn't seem to be an issues.