In this paper, a comparison of efficiencies is put forward for a set of test machines constructed from several different types of low-loss magnetic steels. These are laminated amorphous alloys, 6.5% high silicon steel, and general-purpose low-loss silicon steel. Efficiency and characteristics are compared by experiment. The test switched reluctance motors are shown to have more than 95% efficiency at an output of about 2 kW. The effectiveness of an enhanced winding slot fill factor is also evaluated. The use of the high silicon steel is more practical at improving the efficiency as opposed to the use of increased slot fill factor.