Consider the situation where, in a single network or system, several different types of atomic and nonatomic users coexist and have attained their own optima unilaterally. We call the combination of the optima a "mixed optimum." For a distributed system with identical nodes each having identical arrivals,,we obtain the analytic expression of the unique mixed optimum, where mutual job forwarding among nodes may occur for some atomic users, resulting in paradoxical performance degradation.