US Patent 7457974 Dynamically changing PCI clocks

A method, apparatus and computer-usable medium are presented for dynamically selecting a clock signal used by a peripheral device that is coupled to a motherboard. When the motherboard is powered off, a clock selector sends the peripheral device an internal clock signal from the peripheral device's own internal clock controller. When the motherboard powers up, the clock selector sends the peripheral device an external clock signal from the motherboard.