Here is the framerate and screen tearing analysis of the Forza Motorsport 3 Demo from the same website that provided the Sigma 2 analysis.

Perfect result. Solid 60fps and 0 screen tears during gameplay. Impressive! Replays are locked at 30fps.

http://zoome.jp/ps360/diary/406/

Perfect 60 would be great for multiplayer.

Forza 3 looks great and runs very fluidly... only graphical hitch that I did notice was the track magically disappearing at times during replays, particularly when the camera is sweeping very low to the cars and goes below "track level" as the cars ascend and descend the track's many hills and valleys.

Another poster made a (quite humorous) thread about that issue as well...

http://www.vgchartz.com/forum/thread.php?id=87103

That sounds like an issue with the camera more so than anything to do with graphics. Like it's going under the road so it should be an easy fix?

Turn 10 already knew about it :)

It happens when you use one of the camera angles and the replay camera goes beneath the road. I don't think Turn 10 plan on fixing it because they would need to take away some of the camera angles which would limit replay exporters. The small glitch is worth the pay off.

I doubt it will happen on many race tracks either, only the one's with big elevation changes.

Well Forza 3 is a technical masterpiece. Ive never seen a draw distance with that level of detail on a console game yet. Well done Turn 10, and perfectly locked Framerate to. :)

I was impressed with the demo. I hated Forza 2 and disliked the Dirt 2 demo because of the controls. This felt alot more responsive which is what I like.

Thats great to hear, can't wait to try out the demo on friday...

Actually that is something I don't think is worth the pay off. I would rather have simpler replays that the track disappearing. Doesn't seem like it would take ages to fix it.

The OP of that thread also said the in-car camera was running at 30FPS.  Shows what he knows.