Faced a question couple of time “What are the performance gains in Win 2003 SP2 for SQL Server 2005 as mentioned in: http://www.microsoft.com/technet/windowsserver/sp2/faq.mspx“
2 important performance areas that I know of:
· Optimization done for Dispatch locks (refer to http://download.microsoft.com/download/e/b/a/eba1050f-a31d-436b-9281-92cdfeae4b45/synch_table.doc for more details)
Timer processing done on CPU #0 have significant performance impact on enterprise systems running heavy loads. Systems running 64-bit Windows Server 2003 SP1 and x64 will see more advantage of changes made around Dispatch locks.
· Introduction of new FO_SKIP_SET_EVENT to fix a bug within the sockets API where WinSock would signal an internal event even if SQL didn’t provide it one and nobody was waiting on that. Additional signaling could result in system wide DISPATCH local and thus causing more spinlocks and excessive kernel time.
I would recommend to test the system before applying Windows 2003 SP2 and as mentioned 64 bit system
will see more advantage (especially system showing excessive kernel time and high number of spin locks).