After you stop drooling at the thought of having dual video cards in an SLI setup, you come to realize some practical concerns. Cost is the most obvious one. Most of us struggle to pay $450 for one video card, but spending $900 to $1,000 on two is just ludicrous to many people. Beyond the cost though are other important concerns, like power requirements. More and more power supplies are including the new 6-pin PCI Express power connector, but I have only seen a couple that offer two such connectors. I happen to have one of them for review today -- the Thermaltake 680W Silent PurePower power supply (W0049).