Microprocessors that are designed to perform fewer types of computer instructions but at higher speeds (millions of instructions per second, or MIPS) are known as reduced instruction set computers, or RISC.

The RISC concept has led to a more thoughtful design of the microprocessor, one that includes the following key architectural considerations:

• how well an instruction can be mapped to the clock speed of the microprocessor (ideally, an instruction can be performed in one clock cycle)
• how "simple" an architecture is required
• how much work can be done by the microchip itself without resorting to software help

Because each instruction type that a computer must perform requires additional transistors and circuitry, RISC-based processors offer several advantages over complex instruction set computers, or CISC-based processors:

• Smaller die size, allowing more room for performance-enhancing features such as cache memory, memory management...