title: Does coding towards an interface rather then an implementation imply a performance hit?
body: <p>In day to day programs I wouldn't even bother thinking about the possible performance hit for coding against interfaces rather than implementations. The advantages largely outweigh the cost. So please no generic advice on good OOP.  </p>
  
  <p>Nevertheless in <a href="http://forums.xna.com/forums/p/30645/173406.aspx#173406" rel="nofollow noreferrer">this</a> post, the designer of the XNA (game) platform gives as his main argument to not have designed his framework's core classes against an interface that it would imply a performance hit. Seeing it is in the context of a game development where every fps possibly counts, I think it is a valid question to ask yourself.  </p>
  
  <p>Does anybody have any stats on that? I don't see a good way to test/measure this as don't know what implications I should bear in mind with such a game (graphics) object.</p>