Some background info on MIPS and IRIX if anyone is interested:
MIPS was one of the first RISC architectures around. The first MIPS processor, the R2000 was released in 1985. The first 64-bit CPU ever was the R4000, released in 1992. This was when MIPS was owned by Silicon Graphics, the then technology leader in anything 3D, and they used MIPS chips in their workstations and Onyx graphics supercomputers.
At around 1997 or 1998, SGI and MIPS lost their competitiveness due to bad management. MIPS at SGI hasn't moved forward since 2003 and it got axed in 2006. These days MIPS isn't around for anything mainstream, although they are still very popular as low power chips for use in mobile phones, set top boxes, routers, that sort of thing, although SiCortex makes supercomputers with them.
As for IRIX, it is a pretty cool UNIX OS from SGI that ran on MIPS computers. It was a real time OS, so interactivity was pretty much guaranteed. The computer, no matter how heavily loaded, would still be responsive. XFS, the file system for IRIX (like NTFS for Windows) has the same real time performance guaranteed features like IRIX. IRIX got axed when SGI couldn't afford further development and switched to Linux.
XFS is now open source software, and I enjoy its advanced features on my Linux box, although my cheap and old x86 box doesn't support any of XFS more advanced features (but it is fast, real fast).
C. P. U. Its not a big processor... Its a series of pipes!