A method and system are implemented to measure quantitative changes in display frame content for dynamically controlling a display refresh rate. Specifically, one embodiment of the present invention sets forth a method, which includes the steps of composing a first display frame from a first set of rendered image surfaces, composing a second display frame from a second set of rendered image surfaces, dividing the first display frame and the second display frame into a same number of frame regions. Also, for each of the frame regions, the method also includes the steps of calculating a first set of numerical codes and a second set of numerical codes representative of the content associated with the frame region in the first and second display frame, respectively; and determining an amount of changes in content between the first display frame and the second display frame based on the results of comparing the first set of numerical codes against the second set of numerical code.