Recommend me a gaming desktop

[Rackhir]

Yes, they are SLI linked. I probably bought into the charts on Dell/Alienware's site that shows that dual cards are better than one but that at a certain point the single, newer card is better than older, dual cards. I think I wanted this so that I have a motherboard ready for dual cards to be able to upgrade in the future. I wasn't sure if every motherboard came with the option to have dual graphic cards otherwise.

Getting the SLI graphics cards has nothing to do with if the MB is SLI/Crossfire (the ATI version) capable. That's purely a function of the MB. Pretty much any MB used in a gaming system is going to be capable of at least one, though not necessarily both. Getting an SLI/Crossfire capable MB is one of the things you are paying for in such systems and pretty much only the low end boards these days don't support at least one of them.

MB support for it is mostly down to what licensing fees they want to pay and if the MB has enough PCIe lanes (you really want a minimum of 2 x8 capable slots) to support an SLI/Crossfire setup. One of the big advantages of the Socket 1366 boards vs the socket 1156 boards is that the Socket 1366 boards have a lot more PCIe lanes. So a socket 1156 board might need an addon chip for more.