Abstract: A system is provided that allows for the synchronous operation of a memory controller within a computer when the local bus clock has become inactive for a predetermined period of time. The system includes a circuit that senses the presence of the local bus clock and dependent upon whether the local bus clock is active or inactive causes a switching circuit to switch to a second clock signal that is independent of the local bus clock to run the memory controller. In one embodiment, a pixel clock signal is utilized to run the memory controller when the local bus clock signal is not active.