State vs performance in ASP

Most ASP developers already know that maintaining state in ASP pages comes 
at a performance cost and that you should avoid persisting state when it 
makes logical sense to do so. But did you know that you could be paying a 
performance cost for state management even when your code isn't using it?

The issue is that the ASP engine makes room for the possibility you'll use 
state management features of the session object even if you never refer to 
any of them in code. So, if you know that you aren't using state at all, 
you should add the directive

<%@ EnableSessionState = False %>

to any page that doesn't require the session object. This declaration allows 
ASP to process scripts concurrently instead of sequentially and will improve 
overall performance.