I'm on a 6800GT 256, rolling back to 71:89 did not work. On latest drives I can play without problems up to standard maps...anything larger than that is not useable, game becomes extremely slow. Problem seems to appear after a move sequence (diplomacy and wonder movies for example). ALT-tab'ing solves the lag temporarily.
WarX - you stated that you also use 6800, what drives are you using? Have you made any changes upgrades to get your civ4 running? Have not tried 76.44.
I'm on a 2GB RAM, P3.6Ghz, 6800GT 256. I should not have and performance problems with those specs I think. I might also add that using the lowest graphic settings gives me the same problem.
Take2 has not responded to my ticket yet.