If I am understanding your question correctly, it depends on your motherboard.
Your Intel Core I3-4170 CPU provides you with integrated HD Graphics 4400. If you were to install a discrete graphics card (NVidia GTX or AMD RX) into the PCI-Ex16 slot of your motherboard, your integrated HD Graphics 4400 would probably be disabled and no longer function on their own. You'd use the graphic card outputs instead.
However, on some motherboards, there is a setting in BIOS that allows you to re-enable the integrated graphics even if a discrete graphics card is installed. We would need to know the exact model number of your motherboard in order to say for sure.
-Wolf sends