Complex instruction set computing (CISC)
Single instructions can execute several low-level operations

Load from memory, an arithmetic operation, and a memory store
A=7
A=A* A

CISC processors are capable of multi-step operations
Addressing modes within a single instructions,
hence faster than ISA.
Intel's Pentium is a  CISC microprocessors

Mminimize the number of instructions per program,
sacrifice the number of cycles per instruction.

Reduced Instruction Set Architecture (RISC)
Has a reduced set of instructions.
Reduce the cycles per instruction at the cost of the number of instructions per program

IBM's RISC System/6000 workstation and Macintosh computers use RISC microprocessors.

RISC takes each of the longer, more complex instructions from a CISC design and reduces it to multiple instructions that are shorter and faster to process.