The CGI technology in movie

It's now 2010, and I have seen many movies which are now equipped with CGI technology.
Back to 1970s, CGI technology was introduced in movies, and from time to time, the CGI technology had improved so much, one of the recent movie, Avatar, has a very magnificent scenery in the movie. I watched a video regarding to the making of Avatar. They use real-time performance capture, when I first watched the movie in cinema, I thought all the Na'vi was created by computer but I only knew it that they use such a technology in capture the movement of human.

James Cameron, the director of Avatar, has come out with this idea before Titanic (another of his famous film) came out, and Avatar can only be done in 2009, and he actually said it some scene took 2 years to consider how to shoot and capture. In most of games, normally use low-poly objects because high-polygons required much memory to render, but in movie, for example Avatar, some of the scene they used up to 50 billion polygons, a crazy amount. Compared to graphic in Toy Story, a film of Pixar studio. We can see the huge difference in terms of graphic. When I first watched Toy Story about 10 years ago, I don't know whether how much time they used to produce the film, 2 years? or 5 years?.