The Intel i486 (also called 486 or 80486) is a range of 32-bit scalar Intel CISC microprocessors which is part of the Intel x86 family of processors. The i486's predecessor was the Intel 80386 processor. The first line of 486 processors was introduced in 1989 containing 1.2 million transistors (0.8 micron technology). The i486 was so named without the usual 80-prefix, because of a court ruling that prohibited trademarking numbers (like 80486). Intel dropped number-based naming altogether with the successor to the i486 – the Pentium processor.
From a software point of view, the instruction set of the i486 family is very similar to its predecessor, the Intel 80386, with the addition of only a few extra instructions.