I have on-board video. It is an Sis 650/651/M650/740 Chip set. I have an old pc with an Nvidia Gforce 2mx 32mb PCI. I know this card will perform better than the Sis, but can I disable the on-board system. I know it is a Microstar Mobo with a p4/1.6ghz on it. I have not had the side off yet to see the model.