You will be able select which input the monitor is going to use when you fire up the monitor. But there is no reason to have them both connected. Remove the D-Sub connector and use the DVI. That will give you the best display. Here's why... DVI is digital. D-Sub is analog. Since the card produces a digital signal and the monitor uses a digital signal, there's no need to have the signal converted to analog leaving the card and converted back to digital at the monitor.