The first one is for the Vanila (standard 6800)
And the other one compares a Leadtek 6800gt to a gigabyte 6600gt.
The actual performance of the cards will all be the same unless they are pre-overclocked - BFG do this, but you can always overclock it more your self, and the Leadtek has a nice heatsink to keep it cool in the overclocks. The XFX as I said, have been used in the WR, so is known to overclock extremly well - they don't use conventional cooling, but dry ice, liquid nitrogen etc.
Cisco CCNA, Comptia A+, 1/3 through CCNP