06-24-2008 09:21 PM
The difference is the edition of Microsoft SQL 2005 that they install when on a Server operating system.
SQL 2005 EX is limited to 1 processor, 1GB RAM and 4GB database size
SQL 2005 ST is limited to 4 processors and no RAM limit
See - http://www.microsoft.com/sql/prodinfo/features/compare-features.mspx
If your server ony has one or two processors and 2GB or less RAM, there is no difference unless your database is >4GB.
If you want to have 25 or more concurrent users, you should use a server with the extra RAM additional processors and use the ST edition.