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Intel 80486

The Intel 80486 (i486, 486) is a range of Intel CISC microprocessors which is part of the Intel x86 family of processors.

The 486s are very similar to their immediate predecessor, the Intel 80386. The main differences are that the 486 has an optimised instruction set, has an on-chip unified instruction and data cache, an optional on-chip floating-point unit (FPU), and an enhanced bus interface unit. These improvements yield a rough doubling in performance over an Intel 80386 at the same clock rate. However, some low-end 486 models were actually slower than the highest-speed 386s, especially so with the 'SX' 486s.

There are several suffixes and variants including:

External clock rates include 16MHz, 20MHz, 25MHz, 33MHz, 40MHz and 50MHz. Some 486 motherboards provided unofficial and undocumented support for 60 and 66MHz, however.

The 486 processor has been licensed or reverse engineered by other companies such as IBM, Texas Instruments, AMD, Cyrix, and Chips & Technologies. Some are almost exact duplicates in specifications and performance, some aren't.

The successor to the 486 is the Pentium processor.

See also List of Intel microprocessors

External links

Preceded by:
Intel 80386
Intel microprocessors Succeeded by:
Intel Pentium

Based on material from FOLDOC, used with permission.