(RISC) A processor whose design is based on the rapid execution of a sequence of simple instructions rather than on the provision of a large variety of complex instructions (as in a complex instruction set computer).

Features which are generally found in RISC designs are uniform instruction encoding (e.g. the op-code is always in the same bit positions in each instruction which is always one word long), which allows faster decoding; a homogenous register set, allowing any register to be used in any context and simplifying compiler design; and simple addressing modes with more complex modes replaced by sequences of simple arithmetic instructions.

Examples of (more or less) RISC processors are the berkeley risc, hp-pa, clipper, i960, amd 29000, mips r2000 and dec alpha. ibm's first RISC computer was the rt/pc (ibm 801), they now produce the RISC-based risc system/6000 and sp/2 lines.

Despite apple computer's bogus claims for their powerpc-based macintoshes, the first RISC processor used in a personal computer was the advanced risc machine (ARM) used in the acorn archimedes.