DVI is simply the video signal in a digital format for LCD monitors that up until now had to convert the analog signal into digital in order to display. The conversion decreases the quality of the picture(may not be really that noticable, but it still does). So now video cards offer the signal still in digital format rather than converting to analog and then the lcd having to convert it back, thus resulting in two conversions. Hope this helped a little, its late so my writing skills aren't the best.