I've got a 2x2.8 Ghz Quad Core with 12Gb Ram, i'm editing a AppleProRes422 Video 1080p with FCP but the Real Time playing (with filters applied) is very slow. I'm new in the video world, I come from photography, and I know little about the Editing Hardware.
I would like to know if there's editing cards or other hardware pieces to get a smooth RealTime playback in final cut (i've read something about AJA or Matrox, but I can't understand what type of card i should use...)

Any word will be very helpful!

Thanks (and sorry for language errors! )