Computer simulations were performed to predict the performance characteristics of dual‐energy x‐ray absorptiometry. K‐edge filter techniques were analyzed in detail and compared to 153Gd sources in terms of output intensity, precision, patient dose, image contrast, beam hardening, and marrow fat effects. Similar analyses were performed for two dual‐kV techniques that have been reported in the literature. The simulations indicate that K‐edge filter techniques, or a dual‐kV technique combined with K‐edge filtering, can provide performance capabilities that equal or exceed those achievable with 153Gd systems. A (70/140) dual‐kV technique with conventional (Al or Cu) filtration also has advantages in terms of source output intensity, but is 2–3× inferior to the K‐edge techniques and 153Gd in terms of patient dose and beam‐hardening effects.