1. In a computer system having a device, and a communications link for communicating with said device, a method for dynamically managing power consumption by said computer system comprising: associating a particular device identifier with said device; monitoring communications over said communications link to determine whether said communications include said particular device identifier; withholding a clock input from said device when said communications do not include said particular device identifier; and providing said clock input to said device only when said communications include said particular device identifier; said providing of said clock input causing said device to transition from a non-operational power conservative state to an operational state wherein said device consumes more power than in said non-operational state; establishing a performance requirement for a task to be executed; and dynamically controlling a frequency of said clock input according to the performance requirement established for the task being executed.