Nvidia Tri SLI won't have a long life cycle. Nvidia's next generation high end, codenamed D8E, won't support Tri SLI setups.
Let me remind you, D8E is based on two G92 chips on two PCBs interconnected together, and you won’t be able to make three of these cards work in a 780i motherboard.
You will physically be able to plug in the cards, but they won’t work, as there won’t be any driver support. At the same time, our sources have confirmed that D8E will support Quad SLI, and all you have to do is to plug in two cards and install the driver to support them.
The sad part is that you won’t get much performance increase from it.