In SQL Server 2005 , TempDB plays a significant role in overall SLQ server performance. In earlier versions it was difficult to monitor and troubleshoot the bottle neck.
In SQL Server 2005, you have number of DMVs to see which users are accessing the TEMPDB database , the internal object being used and version Stores size. The DMV are as follows
Note : In SQL Server 2005 these DMVs only applicable to Tempdb
Counters to Monitor Tempdb Row versioning usage
(a) SQL Server:Transaction Object : Version Generation Rate (KB/s)
(b) SQL Server:Transaction Object : Version cleanup Rate (KB/s)
Refer : http://www.microsoft.com/technet/prodtechnol/sql/2005/workingwithtempdb.mspx