This paper examines the problem of high frequency multi-input periodic operation of continuous fermentation process. Based on a-criterion published prevously, it is shown theoretically that a continuous fermentation process under the operation of simultaneous high frequency periodic change of feed substrate concentration and dilution rate is always superior over the steady state operation except at the optimal feed substrate concentration. This, however, is yet to be confirmed experimentally. Finally, via computer simulations, a good correlation between the simulation and theoretical calculation of the percentage of improvements on the process productivity is revealed.