As we mentioned in our previous article HD H.264 decoding on a Mac currently requires a G5. Even the dual G4 Power Macs are not supported. The new webpage reflects this requirement, and all the clips require a G5 to play.
However, it seems that previous article was incorrect as to the requirements for 1920x1080 HD playback, which are now listed:
For 1280x720 (720p) video at 24-30 frames per second:Judging by tests by various people, it seems the above specs are a little conservative. Clean playback can be had on lesser G5s. Note that the clips can technically be played on G4 Macs, but unfortunately, not very smoothly most of the time.
* 1.8 GHz PowerMac G5 or faster Macintosh computer
* At least 256 MB of RAM
* 64 MB or greater video card
For 1920x1080 (1080p) video at 24-30 frames per second:
* Dual 2.0 GHz PowerMac G5 or faster Macintosh computer
* At least 512 MB of RAM
* 128 MB or greater video card
[Update 2005-05-01]
Thanks to the guys who reported that their dual GHz Power Macs will play back 720p24 material with no dropped frames. Using this info and info from a thread at Ars, I've posted a new article listing real-life requirements.