The graphics are rendered on your GPU in digital format then sent to the display. Going to the display via DVI means it stays digital. Going to the display via VGA means it is converted to an analog VGA signal before going thru the cable. When the LCD display receives the VGA signal it then has to convert it back to digital before displaying it (CRT's display in analog, LCDs display in digital), introducing noise and possible fuzzies. If possible, use DVI. If not, don't worry about it unless you are a professional photo/video guy and the fuzzies bug you.