The Reduced Instruction Set Computer, or RISC, is a microprocessor CPU
design philosophy that favors a smaller and simpler set of instructions that all take about the same amount of time to execute. The most common RISC microprocessors are ARM, DEC Alpha, PA-RISC, SPARC, MIPS, and IBM's PowerPC.
Low power has emerged as a principle theme in today’s electronics industry. The need for low power has caused a major paradigm shift where power dissipation has become as important consideration as performance and area. This processor will follow the RISC architecture because it supports a predefined set of instructions. In this all the instructions have same length. RISC processors, first developed in the eighties .The idea was inspired by the discovery that many of the features that were included in traditional CPU designs to facilitate coding were being ignored by the programs that were running on them. Also these more complex features took several processor cycles to be performed. Additionally, the performance gap between the processor and main memory was increasing. This led to a number of techniques to streamline processing within the CPU, while at the same time attempting to reduce the total number of memory accesses.