People just keep in mind that even IF these rumors are true, they could use GPUs based on these cards. So imagine they modified some specs (make it more power efficient) to be able to overclock them slightly. they could easily use another hardware revision.
so as of now, we can really not say these specs are too low.

must-have-list for platforms i don't own yet:
WiiU: Donkey Kong
XBone: Dead Rising 3, Ryse







