They aren't just shrinking it. Steamroller adds dedicated instruction decoders in each module, which seems to be part of the bottle neck right now (two modules share decoders at the moment.) They are making core changes that should increase performance quite a bit. Add that to the improvements that should come from Windows 8 and AMD is inching back. Power is my biggest concern at the moment. Bulldozer is extremely power hungry. If they can cure that and keep cool, then they may have an overclocking beast with Piledriver.