Visiontek has yet to fail me AFI. My 4870 (visiontek) does 870/1100 so far, I ran out of ram clock slider bar.( have a tweaked bios for it now just haven't had time to play with it)
Looks like my scaling calculations were a tad conservative. This ones for you AFI, untweaked backed off ram a tad as i saw no diff in performance...My bios apparently backed off my ram timings when I tried to boot at 2800NB speed ( dont have AOD or k10 installed atm ).....it would have scored higher but I'm just screwing around atm.
Still have a long way to go, and definitely going to need voltmods/better cooling to get up with the top scores.
http://members.cox.net/chewxs/48504.JPG