We have had many come to us to install dual ATI 3800 series cards in their sysytems and they won't fit ! Make sure both slots will accept dual slot cards ! Some motherboards have the top slot too darn close to motherboard components . You MUST be able to see a blank slot opening ABOVE both video card slots . Most of the problems have been with Dell and Gateway systems . They made them for single slot card setups and did'nt allow for dual slot card setups . *** *** Most likely the new nvidia dual cores will be double slot also and will not fit . Just trying to save many from wasting money and sending flaming emails to the companies with no help from them . Not to say they don't deserve getting chewed out . They all advertise dual setup capabilities but are far behind what is coming on the market . *** ***