A load balancer, comprising a network interface, a power conservation unit, and a routing module configured to route client requests received through the network interface to a plurality of servers. The power conservation unit is characterized by having a learning mode and a routing mode. In the learning mode one or more operation parameters of the servers are determined for a plurality of different external conditions and for a plurality of different values of one or more operation parameters of the routing module, and to generate a correlation table between the operation parameters of the routing module and the external conditions. In the routing mode the power conservation unit adjusts the operation parameters of the routing module responsive to the external conditions, using the correlation table.