Specifics on the technology are still being kept under wraps, but a recent demonstration showed six 30-inch Dell displays running together to form one insane 7680 x 3200 resolution surface. The graphics card used in this particular demo sported six DisplayPort connectors, made possible due to the connector's compact size, though a spokesperson said that HDMI and DVI-based cards with fewer outputs should be available as well.
Apparently AMD has coded their driver to tell the operating system that a single huge screen is attached, instead of multiple monitors, thus enabling games to take advantage of the entire surface. Anandtech notes that the upcoming race title Dirt 2 was shown off at 7680 x 3200 with "definitely playable frame rates," for example, while Left 4 Dead on a three monitor, 7680 x 1600 configuration produced better results.
Maximum PC cites 12-20 frames per second performance in a 3DMark 2006 test, which is not what many would consider "playable," but getting that resolution from a single card is nonetheless impressive. Of course this six-connector GPU isn't a production model, but there should be three-connector versions at launch that will allow an ultra-widescreen setup off a single card. AMD didn't announce specific price-points, but did state that Eyefinity-based graphics will make it into desktops and notebooks "at very affordable prices."
The downside to using so many monitors (besides their total price of course) is that their bezels might get in the way. For this, Samsung is reportedly working with AMD to produce ultra-thin-bezel monitors and stands designed with Eyefinity in mind.