AMD's upcoming 45nm Deneb processors will overclock a lot better than the current Phenom processors. Several sites report the Phenom II no longer suffers from the cold bug and that AMD demonstrated a system running over 6GHz with liquid nitrogen cooling, which kept the processor at a chilly -185°C. This clockspeed was achieved on a Gigabyte 790GX motherboard with the Phenom II chip overvolted to 1.9V.
During the press meeting, AMD stressed the Phenom II has lots of overclocking headroom. Good air cooling will take the chip to 4GHz and watercooling or more extreme methods of cooling will take the chip even higher.
As we all know, the Phenom II will be AMD's second 45 nm part (the first is officially the Shanghai server part) that is scheduled to hit Q1 09. This heavily redesigned processor based on the Phenom architecture has already showed some significant per clock performance gains over the older Barcelona product, and AMD considers this to be their best design ever in terms of performance, functionality, and eventual clockspeed. The first desktop products are expected to hit 3 GHz at the top end, but AMD has been hinting that the Phenom IIs can do a lot more in the hands of an enthusiast.
The first leaks were that the Phenom II could hit 4 GHz on air cooling alone, though we obviously wonder how extreme that air cooling is. Well today AMD had some actual demonstrations at their gathering, and the Phenom II was able to hit 5 GHz at 1.6v by using dry ice cooling. Dry ice is CO2, and it goes directly from solid to gas (sublimation) at a temperature of -109.3 F (-78.5C for the rest of the world) at 1 atmosphere. So with some pretty extreme cooling (non-LN) the Phenom II does show that it has some legs in the clockspeed department.