Low end NVIDIA cards can already run in SLI mode with out any additional support. Even on high end cards, the SLI bridge can be removed with a performance hit. These bridge-less, cable-less Radeons will represent the purest vision of a multi-GPU configuration. Rather than purchase a BBA (Built By ATI) master card, any AIB or BBA Radeon X1600 will work together in Crossfire mode. AIB partners could not confirm as to whether separate graphic card families would also work together in Crossfire mode.
Radeon X850 and X1800 will still require a master card to enable Crossfire. Radeon X1300 video cards are already filling the channel here and there, but Radeon X1600 is still not expected to hit channel shelves until December.