There isn't anything revolutionary about the design of the Noctua NH-U14S. It consists of a stack of aluminium fins arranged around a series of six U-shaped nickel-plated copper heatpipes.
Noctua has used a staggered design for the heatpipes which helps to distribute the heat across the aluminium fins more evenly, improving overall heat dissipation. The six heatpipes meet at the CPU block in the middle which is also made from nickel-plated copper. It features a textured design which increases the surface area slightly.
Rather unusually, the NH-U14S is supplied with a 150 mm fan. This features 140 mm mounting points, meaning you would have to replace it with a 140mm model if you're considering alternatives.
This fan is PWM controlled, spinning up to a maximum of 1,500 RPM at full speed. Like the U12S, the U14S is very thin indeed and won't encroach into the RAM areas, even if they are on both sides of the CPU socket.