text: what exactly is a video controller ?? i my device manager it says i'm missing a video controller. i'm guessing that's why i can't watch dvd's ?  could someone please explain what exactly that is ? a video controller or graphics processing unit or gpu (also occasionally called visual processing unit or vpu) is a dedicated graphics rendering device for a personal computer or game console. modern gpus are very efficient at manipulating and displaying computer graphics, and their highly-parallel structure makes them more effective than typical cpus for a range of complex algorithms.