IBM's first major entry into the "RISC" workstations market (architecture-wise), and the basis for the PowerPC CPUs currently employed in (among other things) Apple's Power Macintosh line of computers. While similar to most RISC CPU's of the day in that it used a standard load/store architecture, it doesn't have a very highly reduced instruction set, therefore calling it RISC is a bit of a misnomer (the Alpha series is similar).