S!
I would say that yes, that card will be satisfactory. Comparing to my 2GB 6950 (with flashed bios so that is has the 6970 shader amount, but 6950 clocks), I run the game with Medium settings, and in 2560x1600 resolution, and I get ~25fps on the field, 30-40 over land, and ~45 over the sea. The nasty "
enemy present" bug still sometimes kicks the fps to single digits though.
Note: remember to disable the Ubisoft video! If you have it on, it will most likely drop your fps to half of what they should be. Just delete or rename the video. More info:
http://forum.1cpublishing.eu/showthread.php?t=33628