The performance of minimum variance control systems using controllers performing with different sampling intervals is considered. The controller considered is the generalized minimum variance controller. The analysis is carried out using the simulation technique. Two simulation models are presented to solve this problem. The presented simulation models are applied on a set of processes identified using different sampling intervals. The results are compared by evaluating some performance index defined for the discrete output and input. The performance of the minimum variance control systems is explained in the extreme cases. These cases include very samll sampling intervals compared with the smallest time constant of the continuous process and very large sampling intervals compared with the smallest time constant of the continuous process. The performance using sampling intervals comparable to the smallest time constant of the continous process is explained as well.