Computer system and related image-based rendering devices and display device

The invention discloses image-based rendering devices one of which comprises an input interface, an image processing circuit and an output module, wherein when coupled with a host computer in a demountable mode, the input interface receives a rendering instruction generated by the host computer; the image processing circuit can generate an image frame containing graphical user interface data, computer image data or text data according to the rendering instruction; the output module is used for transmitting the image frame to a display device for displaying; and the data volume of the rendering instruction which is received by the input interface from the host computer is less than the data volume which is transmitted to the display device by the output module. Because the image processing circuit of the image-based rendering device can generate an image frame according to the rendering instruction transmitted by the host computer, the host computer does not need to generate an image frame firstly and then tra