Mini DisplayPort to DVI Adapter : A passive adapter is the most basic type of Mini DisplayPort to DVI adapter that is available. A passive Mini DisplayPort video adapter allows the Graphics Processing Unit (GPU) to communicate with any DVI monitor that does not support the Mini DisplayPort video output on the computer.In contrast, IOGEARs Active Mini DisplayPort to DVI adapter will actively convert the displays DVI signal into a Mini DisplayPort signal for your GPU to interpret. These active adapters are required when connecting more than 2 displays to a video card such as an AMD Radeon GPU that supports Eyefinity technology. The native Mini DisplayPort signals are able to be recognized and controlled by the GPU, ensuring all the connected monitors are synchronized.