The Hopfield model effectively stores a comparatively small number of initial patterns, about 15% of the size of the neural network. A greater value can be attained only in the Potts-glass associative memory model, in which neurons may exist in more than two states. Still greater memory capacity is exhibited by a parametric neural network based on the nonlinear optical signal transfer and processing principles. A formalism describing both the Potts-glass associative memory and the parametric neural network within a unified framework is developed. The memory capacity is evaluated by the Chebyshev–Chernov statistical method.