The Intel i486

The Intel i486, otherwise known as the 80486, was the first tightly pipelined x86 design. Introduced in 1989, it was also the first x86 chip to use more than a million transistors, due to a large on-chip cache and an integrated floating point unit. It represents a fourth generation of binary compatible CPUs since the original 8086 of 1978, and it was the second 32-bit x86 design after the 80386.

A 50 MHz 80486 was reportedly able to perform 41 million instructions per second and was able to reach 50 MIPS peak (see below).

(The i486 was so named, without the usual 80-prefix, because of a court ruling that prohibited trademarking numbers like 80486. Later, with the Pentium, Intel dropped number-based naming altogether.)