E6760 (480 core, DX 11). Looks like Turk to me.
as i said the HD4770 is a high estimate.
just to point out that Black Ops 2 on Wii U run at 880x720 LOLOLOLOLOLOL that is 3.3 times
smaller than the standard 1080p and 6.5 times
smaller than 2560x1600 the resolution I play games on.
at this point i suspect that the Wii U use HD4450.