This month, respected analyst Jon Peddie has his say on CrossFire. As someone who started his career in computer graphics in 1962, he's a man worth listening to!
Quote:
While Nvidia has never denied that SLI’s speedup is application and usage dependent, we were impressed with ATI architects’ willingness to look for ways to make the 2nd GPU useful when applications, user demands, and/or host systems make it difficult for AFR or Scissor mode to produce a solid performance increase. As a result, CrossFire architects added support for two additional modes that SLI' have. (or at least not yet): Supertile and Super AA modes.
Link:
http://www.hexus.net/content/reviews...lld19JRD0xMjY2