Additional workloads are assigned among servers in a power-efficient manner. For each of a plurality of servers, a stored power efficiency/capacity utilization relationship is accessed, current component power consumption values are obtained, and a current power consumption efficiency is calculated. An amount of capacity utilization necessary to perform an additional workload is obtained, and a predicted power consumption efficiency is determined for each server. The predicted efficiency is determined using the current power consumption efficiency of the server and the stored relationship. The workload is then assigned to the server identified as having the greatest predicted power consumption efficiency. Alternatively, the workload may be assigned to the server identified as having the greatest improvement in power consumption efficiency.