I have a 2012 5,1 Hex and the Airplay icon is now available for streaming to my Apple TV. This isn't supposed to happen. It allows me to select my ATV as a 2nd monitor or to mirror my display. But here's the rub. The TV screen just goes black and no picture ever shows up. This isn't support to work at all. Wonder why it is giving me the option. My other Macpro (2008 3,1) also upgraded to Mavericks did not get the Airplay option as expected.