I had similar issues on Windows 7 64bit OS; Lot of these issues will disappear if you are on 32 bit OS.

Take a look at this thread:

http://social.msdn.microsoft.com/Forums/en-US/sqldataaccess/thread/8514b4bb-945a-423b-98fe-a4ec4d7366ea

Basic things:

(1)...

I noticed something interesting: look at these two queries:

SELECT Ord.value('(.)','char(5)') FROM @xml.nodes('/ROOT/Customer/CustomerID') AS x(Ord)

SELECT Ord.value('(.)','char(5)') FROM @xml.nodes('/ROOT/Customer/CustomerID[text()]') AS x(Ord)

The latter outperforms the former eventhough both return same...

The following seems to work faster ( ~69% compared to 95%) even though it still isn't what i expected to see. My guess is that the query cost calculation does...