Hello, I just tried out SLI for the first time and the speed was great before my old cards over heated. I like the idea of SLI as I can use them to improve my speed without buying a new video card every time I upgrade and when that becomes too slow I can put them in my second PC. The issue for me is I like REALLY quiet PCs. The stock coolers do a pretty good job even with the cards up against each other but I see a lot of people try to leave at least 1 space between the cards. The problem for that with me is I use a sound card AND a SAS controller so my slot arrangement for keeping the cards cool is limited. I was thinking of building a new PC and putting one card at the very top and one at the very bottom in an extended case (HAF X) Often they recommend using PCIe slot 1 and slot 2 for SLI. Not sure if that is an old concern or still current.