How well does something like a 8800GT handle dolphin?
Dolphin is CPU bound.
But I think a 8800GT can handle Dolphin in 1080p if given something like a high clocked Phenom 2 or i5-7
Plus you cant compare it like that. Nintendo knows 100% how the GC/Wii works so an emulator would be easier to make. If the WiiU is POWERPC like the Wii and GC it might play Wii/GC games.