Aspects include a pixel source that produces data for a rendered surface divided into regions. A mapping identifies memory segments storing pixel data for each region of the surface. The mapping can identify memory segments storing pixel data from a prior rendered surface, for regions that were unchanged during rendering the rendering. Such changed/unchanged status is tracked on a region by region basis. A counter can be maintained for each memory segments to track how many surfaces use pixel data stored therein. A pool of free memory segments can be maintained. Reading a surface, such as to display a rendered surface by a display controller, includes identifying and reading the mapping to identify each memory segment storing pixel data for regions of the surface, reading such, and updating the counters for the memory segments that were read.
