Between all the previews I have read it appears that basically performance between the two high end cards is about equal at 1600x1200 with 4xAA/8xAF which is the setting I play at (16xAF for me though). I saw Firingsquad mention that the 1.2 patch added some graphic problems to X800 cards and even decreased performance. Unless someone is planning to play multiplayer online I think X800 owners should stick to the 1.1 patch as the 1.2 patch doesn't really offer anything of note to the single player game outside of new bugs - thanks Crytek!!!
I am not a player hater so it is nice to see 6800 owners get the level of performance I have been enjoying in this game. Some of the websites used their own custom demos so that explains some of the performance differences.
I will say right now I tend to look at the custom demos websites use to benchmark video cards as I tend to look with a slightly suspicious eye aat any "custom" demo ATI or Nvidia provides.
*Edit* The Hexus preview showed a performance drop between the 1.1 and 1.2 patch - I am absolutely positively certain that this was unintentional on Crytek's part!