24 Facts About Intel 486

Intel 486, officially named i486 and known as 80486, is a microprocessor.

The iIntel 486's improved performance is thanks to its five-stage pipeline with all stages bound to a single cycle.

At the announcement, Intel 486 stated that samples would be available in the third quarter and production quantities would ship in the fourth quarter.

Intel 486 attempted to prevent AMD from selling the processor, but AMD won in court, which allowed it to establish itself as a competitor.

The AmIntel 486 series was completed with a 120 MHz DX4 chip in 1995.

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AMD's long-running 1987 arbitration lawsuit against Intel was settled in 1995, and AMD gained access to Intel's 80486 microcode.

However, these chips could not match the Intel 486 processors, having only 1 KB of cache memory and no built-in math coprocessor.

Cyrix released a derivative Intel 486 processor called the 5x86, based on the Cyrix M1 core, which was clocked up to 120 MHz and was an option for Intel 486 Socket 3 motherboards.

Intel responded by making a Pentium OverDrive upgrade chip for 486 motherboards, which was a modified Pentium core that ran up to 83 MHz on boards with a 25 or 33 MHz front-side bus clock.

Instruction set of the iIntel 486 is very similar to the i386, with the addition of a few extra instructions, such as CMPXCHG, a compare-and-swap atomic operation, and XADD, a fetch-and-add atomic operation that returned the original value .

IIntel 486's performance architecture is a vast improvement over the i386.

Processors compatible with the iIntel 486 were produced by companies such as IBM, Texas Instruments, AMD, Cyrix, UMC, and STMicroelectronics .

Motorola 68040, while not iIntel 486 compatible, was often positioned as its equivalent in features and performance.

However, the iIntel 486 had the ability to be clocked significantly faster without overheating.

Early iIntel 486-based computers were equipped with several ISA slots and sometimes one or two 8-bit-only slots .

Late iIntel 486 boards were normally equipped with both PCI and ISA slots, and sometimes a single VLB slot.

One of the earliest complete systems to use the iIntel 486 chip was the Apricot VX FT, produced by British hardware manufacturer Apricot Computers.

Later iIntel 486 boards supported Plug-And-Play, a specification designed by Microsoft that began as a part of Windows 95 to make component installation easier for consumers.

Computers based on the iIntel 486 remained popular through the late 1990s, serving as low-end processors for entry-level PCs.

Production for traditional desktop and laptop systems ceased in 1998, when Intel 486 introduced the Celeron brand, though it continued to be produced for embedded systems through the late 2000s.

Windows 2000 could run on a iIntel 486-based machine, although with a less than optimal performance, due to the minimum hardware requirement of a Pentium processor.

However, as they were overtaken by newer operating systems, iIntel 486 systems fell out of use except for backward compatibility with older programs, especially given problems running on newer operating systems.

However, DOSBox was available for later operating systems and provides emulation of the iIntel 486 instruction set, as well as full compatibility with most DOS-based programs.

In May 2006, Intel announced that production of the i486 would stop at the end of September 2007.