http://blog.alecl.com/archive/2007/10/17/tempdb-contention-and-trace-flag-1118.aspxIt has been recommended for SQL 2000 and 2005 to enable trace flag 1118 to disable mixed extent allocation. Recently a hotfix came out for SQL Server 2005 SP2 that resolved a potential contention issue with the flag itself: http://support.microsoft.com/kb/936185enCommunityServer 2.1 SP2 (Build: 61129.2)