OS X recognises the HD-DVD from a 360 instantly. Doesn't mean it can play HD-DVDs though. DVD Player doesn't contain the drivers to allow this. When this is done, I have no idea what the performance is going to be like. On the 360 all 3 cores are at maximum load, and the ATi chip is also doing some of the decoding on the GPU. So it might kill all but the fastest Macs.