In order to prevent connection leaking problem, any database operation should open and close in one unit operation by default. That is also smart not stupid. Please read Performance Considerations for Entity Framework Applications from following url: http://msdn.microsoft.com/en-us/library/cc853327.aspx. Hope you can get some hint there.
Generally speaking, performance of entity framework is better than LINQ but poorer than directly SQL.
If the performance of your operation does affect your whole operation, you might think about to use SQL rather than entity framework.
Generally speaking, performance of entity framework is better than LINQ but poorer than directly SQL.
If the performance of your operation does affect your whole operation, you might think about to use SQL rather than entity framework.