I picked up one of these the other day. It didnt come with any installation media, so I wont be able to run IRIX at the moment. Luckily, there are a couple of *nix distributions available for it. I will upload some pictures and maybe a video once the box is up and running. My O2 came with 256Mb or RAM and a 9.1Gb SCSI hard disk. The CPU runs at 300Mhz.
The SGI O2 is an entry-level Unix workstation introduced in 1996 by Silicon Graphics, Inc. (SGI) to replace their earlier Indy series. Like the Indy, the O2 used a single MIPS microprocessor and was intended to be used mainly for multimedia. Its larger counterpart was the SGI Octane. The O2 was SGI’s last attempt at a low-end workstation.
The O2 uses the CRM chipset that was specifically developed by SGI for the O2. It was developed to be a low-cost implementation of the OpenGL 1.1 architecture with ARB image extensions in both software and hardware. The chipset consists of the microprocessor, and the ICE, MRE and Display ASICs. All display list and vertex processing, as well as the control of the MRE ASIC is performed by the microprocessor. The ICE ASIC performs the packaging and unpacking of pixels as well as operations on pixel data. The MRE ASIC performs rasterization and texture mapping. Due to the unified memory architecture, the texture and framebuffer memory comes from main memory, resulting in a system that has a variable amount of each memory. The Display Engine generates analog video signals from framebuffer data fetched from the memory for display.
For more information about the o2, take a look at this page.