I also think that the RV740 in the HD 4770 has the most chances to be the choosen one.
If only because Nintendo started working on the hardware long before the AMD 6 and 7 series mobility cards appeared, and if Nintendo is known for something is for picking already proved hardware to use on their consoles.
Please excuse my bad English.
Currently gaming on a PC with an i5-4670k@stock (for now), 16Gb RAM 1600 MHz and a GTX 1070
Steam / Live / NNID : jonxiquet Add me if you want, but I'm a single player gamer.