respond too slowly to an out of sync condition or 2 would snap the slave pulse stream into synchronization with the master pulse stream causing a visual distortion an advantage of the present invention is that the convergence time i e how quickly the slave pulse stream can be synchronized to the master pulse stream can be programmably adjusted via rate controller circuit 314 that is the amount of time i e in pixel pulses added to or removed from the slave pulse stream during each iteration of the loop will determine how quickly the loop converges and achieves synchronization for gross adjustments the loop may be adjusted more coarsely i e more pulses added removed during each loop iteration when the signals are grossly out of synchronization and more finely i e fewer pulses added removed during each loop iteration when the signals are closer to being synchronized this produces a dynamically self adjusting phase locked loop that is quick to respond but stable enough to prevent visual distortions the present invention has been described in a multi display computer system wherein one computer drives each display in other embodiments however a single computer may have multiple processors wherein each processor generates video and or computer graphics images for a corresponding display device moreover each computer described herein may be for example a general purpose computer such as a personal computer workstation or mainframe or may be a special purpose computer such as a video player game console or the like one skilled in the relevant art will recognize other arrangements that can benefit from without departing from the scope of the present invention in one embodiment the invention is implemented primarily in firmware.