A system and associated method for optimizing power consumption of a data center by dynamic workload adjustment. A current workload distribution of the data center is shifted to an optimal workload solution that provides acceptable level of service with the least amount of power consumption. The sum of power cost and migration cost that corresponds to the optimal workload solution is the lowest among all sums that correspond to respective candidate workload solutions. The power cost is determined by a maximum temperature of the data center and accompanying cooling cost for each candidate workload solution. The migration cost is determined by performance degradation that occurs during shifting a workload distribution of the data center from the current workload distribution to each candidate workload solution.