Method of and apparatus for reducing power consumption within an integrated circuit

An integrated circuit comprising a plurality of processing cores (4, 6, 8, 20), characterised by comprising electrically controllable switches (14, 16, 18) for controlling the supply of power to one or more of the processing cores (4, 6, 8), a memory (40, 42, 24) for saving state data from at least one of the processing cores (4, 6, 8) and a controller (60) adapted to control the supply of power to one or more of the processing cores such that processing cores can be de-powered.