Why execute stored procedures is faster than SQL query from a script?

Question

In fact, if I call the stored procedures from my application, I need a connection to my DB.

So, why calling a \"stored procedures\" should be faster than \"passing a

Answer 1

stored procedures are compiled and cached. But SQL statements will be compared to existing execution plans and if a match is present used, thus nullifying somewhat any advantage.

Whats the actual performance difference after a number of executions ?