Hmm at one time apple broke down the requirements for 720p and 1080p hd video for PowerPC. They said the 1.67 or faster g4 (ddr2 models only) or g5, with 128mb vram, 1gb ram, could do 720p...back in the tiger days when the os didn't steal all of your resources and alias's didn't consume an entire megabyte anything was possible. I have trouble playing 480p youtube content in leopard on a 1.42 emac w/ 1.5gb, radeon 9600 64 mb vram & gpu oc@ 50%. via aticellerator, tiger was flawless.