So not a DVI to DVI cable, a HDMI to DVI cable? Or do you have some converters in the mix? I need the Inspiron 660 service tag number to know if there is an added video card installed. Send it to me via Private Message.
Regardless of whether you use the $99 ViewSonic VA2055SM VGA in or DVI in, the ViewSonic VA2055SM will only do 1920x1080 60Hz. You are not going to "see" the difference between its VGA and DVI.