We’re hearing reports that OS X Mountain Lion’s AirPlay Mirroring feature is not supported on all Macs. The video we posted last night that shows the feature in action uses a MacBook Pro, and it has been working on our 1.8 GHz MacBook Air. It’s not working, though, on our 2.4 GHz 2010 Mac mini or 2010 MacBook Pro with a 2.66 GHz processor and 4GB of RAM.

Some are thinking that Apple is restricting dual-core Macs, but our MacBook Air is dual-core. We’re not exactly sure which Macs are restricted, so check if AirPlay is present for you and let us know in the comments (remember that you need AppleTV 5B2 on your AppleTV for this to work).

AirPlay could be limited to Core  i5/i7s?

In any case this is a Beta and support for more Macs likely could happen.