AirPlay Mirroring will only work if you have the HD 3000 or HD 4000 as your GPU as Apple is using QuickSync now in 10.8 to render the display for AirPlay Mirroring.
AirPlay Mirroring will only work if you have the HD 3000 or HD 4000 as your GPU as Apple is using QuickSync now in 10.8 to render the display for AirPlay Mirroring.