It is convenient to define the spin-torque switching efficiency in nanostructured magnetic tunnel junctions as the ratio between the free-layers thermal activation barrier height and the threshold switching current . Recent device exploration has led to occasional observations of spin-torque induced magnetic switching efficiency in magnetic tunnel junctions that exceeds the macrospin limit by a factor of 2–10. In this paper we examine the possible origins for such enhancement, and materials properties that may allow the full realization of such enhancements.