We were intrigued with H.264 content and the ability to play it back, and we spend two days of testing and finally came to some conclusions. At this time there is no graphic card hardware acceleration for this fancy codec.Check out there test report over here
It's very CPU dependent and we have some advice for both Intel, AMD and Apple computer users.
Playing H.264 content on your PC

The Inquirer has taken a look at playing H.264 content on your PC, without graphics card hardware acceleration (which isn't available yet).