Computer Hardware Terms, Glossary and Dictionary
The 486 processor (or 80486 processor) family was introduced in 1989 by Intel. Lack of significant enhancements over than the 386, it had more transistors and could run at higher clock speeds. The 486 processor had two versions: 486 SX with no math co-processor and the standard 486 DX versions. The 486 initially ran at clock speeds of 25 MHz (SX only) and 33 MHz. The more advanced versions of 486 such as 486 DX-2 can run at speeds of 50, 66 and 75 MHz, and then 486 DX-4 can run up to 100 MHz.