IA-32 (Intel Architecture, 32-bit), also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture. This architecture has defined the instruction set for the family of microprocessors currently installed in most personal computers in the world, although it is now being supplanted by x86-64.