You should explain 'special architecture'. Gamecube, Wii and WiiU all used PowerPC, just like Xbox 360 and PS3. They also used normal graphic cards. So... what's special about the architecture?
The way the Gamecube/Wii GPU worked for example.
Or going with an extremely low clocked triple core PPC while everyone else was shifting to more cores and x86 Nintendo stayed with that three cores and lower clock than everyone else. Even a quadcore 1.6GHz PowerPC might have helped. x86 likely even more.
And no, those PPC 750 derived cores whwen't exactly like the Power based CPU's of Xbox 360 and PS3.
Then there was an own API. At least they didn't go for a graphics architecure no one else used like with the 3DS.