The SGI Onyx family of machines are basically SGIOrigins with very fancy graphics heads on them. Think of a 15U graphics "brick" with 1GB of texture memory pushing several billion pixels/sec to multiple displays and you have the IR4 g-brick, which sits on top of half a rack worth of CPUs and memory to make up an Onyx. Onyxes are used mostly by post production houses and people working with massive 3D models or simulations.
They run Quake pretty well too.
