The Nintendo 64 was the culmination of work by Nintendo, Silicon Graphics, and MIPS Technologies. The SGI-based system design that ended up in the Nintendo 64 was originally offered to Tom Kalinske, then CEO of Sega of America by James H. Clark, founder of Silicon Graphics. SGI had recently bought out MIPS Technologies and the two companies had worked together to create a low-cost CPU/3D GPU combo that they thought would be ideal for the console market. A hardware team from Sega of Japan was sent to evaluate the chip’s capabilities and they found some faults which MIPS subsequently solved. However, Sega of Japan ultimately decided against SGI’s design. In the early stages of development, the Nintendo 64 was referred to by the code name “Project Reality”. This moniker came from the speculation within Nintendo that the console could produce CGI on par with then-current supercomputers. In 1994, the console was given the name Nintendo Ultra 64 in the West. – [Info from wikipedia]
Thanks to MathUser for some of these scans!