A system, method and computer program product for managing power consumption in a system comprising at least two computing devices. The at least two computing devices are organized as part of active computing device group or a ready computing device group, the ready computing devices configured into various modes of readiness including a standby mode, a hibernating mode, and a power-off mode. A control device receives obtained sensed parameters indicative of the processing load at the group of active computing devices and determines a "Readiness" index value representing a state of system readiness which is a function of a transition time parameter representing a time for moving one or more computing devices from the second group of ready computing devices to the first group of active devices in response to a service level violation. To achieve maximum power saving and yet meet various performance targets, the ready computing devices are dynamically allocated from amongst three states: standby, hibernating or power-off, based on the current readiness index value.