A video-resolution frame buffer system with 32 bits per pixel is described. The system includes, in addition to standard features for limited zoom and pan, an arithmetic unit at the update port which allows local computation of many frequently-used pixel-level functions combining stored pixel values with incoming pixel values. In addition to the standard arithmetic and logical functions there are functions for sum to maximum pixel value and difference to minimum pixel value. Comparisons between incoming and stored data are used to implement conditional writes based on depth values for depth-buffer algorithms. Update and refresh ports are designed for a wide range of flexibility allowing simultaneous use by separate tasks and various functional rearrangements of the 32-bit pixel words. The memory architecture, refresh and update ports are described. Examples of widely divergent modes of operation are provided.