The PCI Express Special Interest Group (SIG) has announced a new cabling standard which will allow PCI express cards to move out of the computer chassis , This will allow for products like an external graphics module which will link to your computer through a cable.
There are a lot of reasons one would want to do this, the first and foremost being cooling .If u have seen the new 8800GTX by Nvidia you would have noticed how big it actually is , now imagine two of these monsters in SLI in your box and with overclocking becoming more popular nowadays these cards tend to run quite hot, and cooling them becomes another issue , for such a configuration you would be better off opting for a water cooled solution rather than taking chances with cooling fans .
Another reason seems to be more of a gamer’s dream rather than reality but someday it might just turn out to be true, take for example quad SLI, which connects four graphics cards, in the future we may have an interface which connects say 6 or 8 cards , It would make more sense to move such a graphics unit away from the chassis and into a different box,rather than trying to squeeze in so many slots onto the main-board.
Asus has already demonstrated this technology for laptops at CES with the ASUS XG station and this is an excellent example of what the technology can do.