>Are the various engines (eg query optimizer, storage engine, etc) the same in all editions (eg Standard, Enterprise), and simply have certain capabilities enabled or disabled? Asking because a contractor is trying to tell us that the Enterprise query optimizer is better/faster than the Standard optimizer. I have been searching/googling on this issue, and have not seen anything clearly saying so one way or the other.
>
>I understand that new versions are faster than old versions, for example 2008 is faster than 2000. Just asking whether, within a single version, if the editions are all using the same engines.

This is very interesting question. I know that, for example, indexed views may work differently in Standard vs. Enterprise version

(see this blog post for details

http://beyondrelational.com/quiz/sqlserver/general/2010/questions/4/sqlserver-quiz-general-2010-pinal-dave-how-many-clustered-indexes-will-you-have.aspx

).

I suggest you to ask your question either in T-SQL or SQL Server Database Engine forum at MSDN. There are several MS employees answering questions who will know the answer to this question first hand.