Intel 80486
The Intel 80486 microprocessor (alias i486 or Intel486) was a higher performance follow up on the Intel 80386. Introduced in 1989, it was the first tightly pipelined x86 design as well as 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.
A 50 MHz 80486 executed around 40 million instructions per second on average and was able to reach 50 MIPS peak performance.
The i486 was without the usual 80-prefix because of a court ruling that prohibited trademarking numbers (such as 80486). Later, with the introduction of the Pentium brand, Intel began branding its chips with words rather than numbers.
Read more about Intel 80486: Background, Improvements, Models, Other Makers of 486-like CPUs, Motherboards and Buses, Gaming, Obsolescence