With Haswell, you’re going to see a big push for energy efficiency. The name of the game right now is mobile. While I like to think the desktop (especially the enthusiast desktop) market is still here for showing the best of the best, and what these CPUs are capable of when you build a balls-the-the-wall system around them. As you can see, Intel did tweak quite a bit with Haswell and, while not earth shattering, should still give some noticeable performance benefits. However, while there is increased performance, energy efficiency appears to have been their main focus.
Intel i7 4770K – Haswell – CPU Review | Overclockers