They are two totally different things. Nvidia's 3d Vision uses glasses, a 120Hz display, a compatible video card, and game to create a 3d image. Eyeifinity is just ATI's marketing name for running multiple displays on their new cards that support 3+ displays.
Best answer selected by liquidsnake718.
eyefinity seems more useful for all types of pc users, even for docs, xlx, ppts, or even multimedia, you can have two or even 3 screens. Which makes Nvidias 3d vision look so amature for gamers and ppl that dont have any time but to put on some hardware and act like johnny pnemonic... or whatever
hope it is not to late to point out that nvidia will be getting its own version of eyefinity in a driver release sometime after the new fermi cards come out.
Wow, thats great... hopefully we wont have to use that display port... the only problem also is you would have to use SLi which would cost a fortune. i can already run eyefinity with my single 5850 which cost $280...