The invention concerns a computing system comprising: a plurality of islands capable of operating in one of a plurality of operating modes, a first island being coupled to a first island control circuit and a second island being coupled to a second island control circuit; a first mediation circuit coupled to the first and second island control circuits and adapted: to receive a first request from the first island control circuit to change a current operating mode of the first island; to receive a second request from the second island control circuit to change a current operating mode of the second island; and to control a first voltage supply circuit and/or a first clock generator to change a voltage and/or clock signal supplied to the first and second islands based on the first and second requests.