Adobe says 'Supported graphics cards for GPU Accelleration:'
I think that would imply the feature will only work with those cards.
If that's the case.. and playback for users of a cheap GPU is just as crappy as it is in CS4, then this Mecury Playback is a total con. I mean c'mon, how many video editors out there have a Quadro sitting in their desktop, I doubt there are even many gamers with one.
I'll hold out and see for now, but if Adobe don't streamline the performance of Premiere pretty sharpish, I'm moving to Final Cut