What we really can't do yet in realtime is ray-tracing. Fastest cards now can do about 3 fps in ray-tracing modes.
Thats wrong Intel Knights ferry can raytrace in realtime, though i think they used 4 servers with multiple of this Knights ferry cards. and then streamed it to a laptop:
http://www.wolfrt.de/
I did see more of that sort movies a few year ago already. I'm not sure what they are doing but there is no real ray-traycing going on. Looks more like a just a few objects use a light-way ray-traycing.
Ray traycing basically means following the ligh-waves (a light-wave will bounce to a surface and part of it then go on and bounce to another surface and so on) (this bouncing they cal mirroring). One trick they can do is reducing the number of times a light wave bounds. Then they can tell you they are doing some real-time ray-traycing but they are not really getting the ray-trace affect. To really get a nice ray-tracing effect you need to have between the 9 and 16 bounces.
And then of course it looks like they use it on some objects and not on all. I’m not sure how they do that but it looks that way and sins ray-tracing is all about the way light-waves move you really need to do some ray-tracing on everything. (It looks like any light-waves only bounce to the objects they are using to show this so-called ray-tracing)
You see the same trick in this picture.

They use some form of real-time ray-traycing but it does not really looks very good. Look at the road that just very bad.
Now also look at these pictures:




Now that is real ray-traycing. And for your information. Yes they are all computer-created. These are none real pictures. Ray-tracing really will be the next big thing.