I am trying to play 1280x720 H.264 files on my ATV. They play but the framerate is so poor they are not watchable. I am using nitoTV with the extra codecs installed (Perian).

What codec is out there that does work well? Or is the ATV unpowered that it cannot handle these files?

I'm having problems viewing 720P content on my MBP using Perian 1.0.. guess there's a bug in that release for 264 files.