Defeh: I believe IFH Dynamic Power refers to NAD's powerdrive function. This is the ability of the NAD amplifier section to "temporarily" steer power from one side of the amplifier's power supply, to the side which has a temporary power need.
A temporary power need would be the dynamics of an audio track. This is very evident in multi-channel soundtracks of movies, but it is needed in music passages which complex pieces. This temporary redirection of power allows the receiver to easily handle these dynamics. This is accomplished by supplying a second rail from the other power supply to the amplifier section.
Pretty cool stuff. I think that Carver was the first to implement this, but I could be wrong.