Well, as far as I know HDMI 1.3a (the output the PS3 uses) doesn't support 2 1080p pictures at a time as it's max res is only 2560x1600. That's more than 2x the pixels of 1920x1080, but there is no way to fit 2 1080p pictures in there side-by-side nor on top of each other (which are the techniques for sending 3D pictures from source to TV).
I wonder if Sony manages to patch that in order to support 1080p48 3D, but I wouldn't be surprised if that wasn't possible.







