We propose a technique to reduce the energy consumption of the frame buffer memory, based on the spatial locality of images and display frames. Our scheme reduces energy by selectively avoiding reads from the frame buffer when identical adjacent pixels are detected. This is made possible by using an auxiliary memory that stores the locality information. The proposed architecture allows to dynamically update the locality information, and, unlike previous approaches, it works virtually independent of the size and position of the updates of the display frames. Experimental results evaluated on a set of typical graphical applications show a reduction of about 40% of frame buffer reads.