You've got to be kidding me. Tell me it isn't true. Just upgraded to Mountian Lion to get the airplay for Apple TV and now see it doesn't work on my 2009 iMac. This seems like a really bad thing for Apple to do to its loyal customers, and something they definitely don't tell you about when touting the airplay features of Mountain Lion. Any way around it?
iMac, OS X Mountain Lion (10.8.1)
The requirements are clearly displayed. ML mirroring requires tech in the new chips for video encoding, it's a hardware limitation.
http://support.apple.com/kb/HT5404?viewlocale=en_US&locale=en_US
http://en.wikipedia.org/wiki/Intel_Quick_Sync_Video
http://www.apple.com/osx/specs/
AirPlay Mirroring
Requires a second-generation Apple TV or later. Supports the following Mac models:
You can try Airparrort, which utilizes the CPU, but in turn has mixed reviews.
Air Play Mirroring doesn't work on Mac's older than 2011?
