This is one of my Silicon Graphics workstations, an Indy R4600. It has no secondary cache (PC means it only has Primary Cache) a low processor clock speed and only 32MB of memory.
The computer is named Marune, after a book written by Jack Vance.
Due to the 8 bits graphics it is not really useful as a graphics workstation even though it uses hardware dithering to give the impression that it supports more than 256 colors. On the other hand, the R4600 is still a cool development machine for non-demanding applications, like Perl programming. It also can be used as a web server running, for example, the Apache web server.
The Indy R4600 is currently in storage in the Netherlands.