Depth buffer bandwidth minimization with depth filter plays an important role in designing low power graphics processors. In this paper, an efficient adaptive tile depth filter (ATDF) algorithm is proposed. The key concept is to consider more occlusion conditions in order to achieve better performance. Two existing algorithms, Z/sub max/ and Z/sub max/ algorithms, are integrated to detect both occluded and non-occluded fragments. Moreover, two new techniques, coverage mask and adaptive tile mode, are proposed to further improve the performance. Experiments show that the proposed algorithm can filter out up to 85% fragments to reduce 40% memory bandwidth for test applications with complex scenes, which outperforms the previous works.