i486

The <a href="/facts/Intel/SMF0gJJX">Intel</a> 486, officially named i486 and also known as 80486, is a <a href="/facts/Microprocessor/Fx9CaQht">microprocessor</a> introduced in 1989. It is a higher-performance follow-up to the <a href="/facts/I386/ag5eSgWv">Intel 386</a>. It represents the fourth generation of <a href="/facts/Binary_compatible/7lkFAUfv">binary compatible</a> CPUs following the <a href="/facts/Intel_8086/sS9dlSdK">8086</a> of 1978, the <a href="/facts/Intel_80286/rucEU93g">Intel 80286</a> of 1982, and 1985's <a href="/facts/I386/ag5eSgWv">i386</a>.
It was the first tightly-<a href="/facts/Instruction_pipeline/3zy6CcX1">pipelined</a> <a href="/facts/X86/Kypq5fgu">x86</a> design as well as the first x86 chip to include more than one million transistors. It offered a large on-chip <a href="/facts/Cache_(computing)/gmJYN8wm">cache</a> and an integrated <a href="/facts/Floating-point_unit/XWTW2AbF">floating-point unit</a>. When it was announced, the initial performance was originally published between 15 and 20 <a href="/facts/VAX_Unit_of_Performance/1fxHQlnT">VAX MIPS</a>, between 37,000 and 49,000 <a href="/facts/Dhrystone/7obFPy8m">dhrystones per second</a>, and between 6.1 and 8.2 double-precision <a href="/facts/Whetstone_(benchmark)/Vje1sVrJ">megawhetstones per second</a> for both 25 and 33 MHz version. A typical 50 MHz i486 executes 41 million <a href="/facts/Instructions_per_second/N23PAFGV">instructions per second</a> Dhrystone MIPS and <a href="/facts/SPECint/QIuqwP8S">SPEC integer</a> rating of 27.9. It is approximately twice as fast as the i386 or i286 per <a href="/facts/Clock_signal/9UfTzGHx">clock cycle</a>. The i486's improved performance is thanks to its five-stage pipeline with all stages bound to a single cycle. The enhanced FPU unit on the chip was significantly faster than the <a href="/facts/I387/y8X9HnLL">i387</a> FPU per cycle. The i387 FPU was a separate, optional math coprocessor installed in a motherboard socket alongside the i386.
The i486 was succeeded by the <a href="/facts/Pentium_(original)/dqChAmxz">original Pentium</a>. Orders were discontinued for the i486 on March 30, 2007 and the last shipments were on September 28, 2007.

i486 open-in-new

i486