The DeskStation system looks like many PC clones because it is based on an AT motherboard. The basic difference is the additional logic required for the R4400 bus to communicate with the EISA bus. The memory bus is only 32 bits wide, while the CPU itself has a 64-bit-wide path; therefore 512K of secondary cache is used to enhance performance.
For a short time rPC44 support was being worked on. It worked for one person. However, the perception was that it never reached any functional state. The rPC44 code has therefore been removed from Linux.
PC Magazine Dec 7, 1993 v12 n21 p39(1) DeskStation's MIPS-based system targets NT work. (DeskStation Evolution Series rPC/44 microcomputer)