A graphics processing unit (GPU) is provided. The GPU includes a command stream parser (CSP). The CSP receives a command list from a display driver and parses commands in the command list to determine a rendering mode of the GPU and perform a graphics rendering pipeline for graphics processing according to the rendering mode. When the CSP determines that at least a specific CSP command is not included in the command list, the CSP determines that the rendering mode is a first rendering mode. When the CSP determines that the specific CSP command is included in the command list, the CSP determines that the rendering mode is a second rendering mode. In the second rendering mode, the CSP divides a rendering target into tiles, obtains first drawing commands from the command list according to the specific CSP command, and executes the first drawing commands for each tile.