The SGI IRIS 4D series was a line of workstations from Silicon Graphics built in the late-1980s through mid-1990s. They were the first SGI workstations to use the MIPS architecture. The line culminated with the Crimson which was produced until 1997.
The SGI IRIS series was a line of terminals and workstations from Silicon Graphics built in the 1980s. They used the Motorola 68000 family of processors originally, but moved to early-generation MIPS processors later on.