A computer system is provided having at least one processing resource, at least one power resource and at least one redundant power resource. The at least one processing resource is operable to exploit a greater level of power than is provided by the at least one power resource. The at least one processing resource is configured to exploit power provided by both the at least one power resource and the at least one redundant power resource, at a time when both the at least one power resource and the at least one redundant power resource are both operable to provide power. The at least one processing resource is further configured to limit its power consumption to the power supply capability of one of the power resource and the redundant power resource when one of the power resource and the redundant power resource is not available