What is the difference between i386, i486, i586, i686, i786


Ever wondered what are those words i386/i486/i586/i686/i786 that comes after the name of RPM / DEB packages?
When it comes to understanding the compatibility of a package between different architectures, knowing these terms become important. The above coined terms are Processor architectures. Let’s have a look below…

i386     -     Intel i386/80386   (in 1985)          or          AMD386 / AM386 (in 1991)

i486     -     Intel i486/80486   (in 1989)          or          AMD486 / AM486 (in 1993)

i586     -     Intel Pentium         (in 1993)          or          AMD-K5 (in 1996)

i686     -     Intel Pentium Pro (in 1995)          or          AMD-K6 (in 1997)

i786     -     Intel Pentium 4      (in 2000)          or          AMD-K7 (in 1999)

Intel i386/80386 was introduced by Intel in 1985. It was a a 32-bit microprocessor.
As the original implementation of 32-bit extensions of 8086 architecture, the 8086 Instruction set, Programming model, Binary encodings are still the common denominator for all 32-bit x86 processors. The set of processors compatible with 80386 is collectively termed as x86 or i386 architecture. But Intel prefers the name IA-32.
Read more about Intel i386 here

The AMD386 / AM386 was released by AMD in 1991. It was a 100% compatible clone of Intel 80386. This was the processor that placed AMD as a legitimate competitor to Intel, rather than just a second source for x86 CPUs.
Read more about AMD386 here

NOTE: Packages that are compiled for i386 architecture, are compatible with i386, i486, i586, i686 & i786 architectures.

Intel i486 was released in 1989. It was a was a higher performance follow up on the Intel 80386 processor. The i486 wasn’t officially branded as 80486, because the court ruling prohibited from trademarking numbers. And later on, Intel began branding it’s chips with words.
Read more about Intel i486 here

The AMD486 / AM486 was released by AMD in 1993.
Read more about AMD486 here

NOTE: Packages that are compiled for i486 architecture, are compatible with i486, i586, i686 & i786 architectures.

Intel i586 was released in 1993. It was brand named Pentium. Also called P5, meant to be the 5th generation of x86 micro-architecture. In 1996, Pentium MMX was released based on this processor. It added new MMX instructions.
Read more about Intel i586 here

AMD K5 was released in 1996. It was AMD’s first x86 processor to be developed entirely in-house.
The K5 lacked MMX instructions, which Intel had started giving with this genre.
Read more about AMD K5 here

NOTE: Packages that are compiled for i586 architecture, are compatible with i586, i686 & i786 architectures.

Intel i686 was released in 1995. It was brand named Pentium Pro. Also called P6, meant to be the 6th generation of x86 micro-architecture.
Read more about Intel i686 here

AMD K6 was released in 1997.  It included MMX instructions and an FPU.
It was complemented by AMD K6-2 in 1998, which introduced AMD’s 3D-Now!
AMD released AMD K6-III was released in1999
Read more about AMD K6 here

NOTE:Packages that are compiled for i686 architecture, is compatible with i686 & i786 architectures.

Intel i786/80786/P7 was introduced in 2000. It was brand named Pentium 4.
It must be noted, these are unofficial names. Official name is P68 / Intel NetBurst Microarchitecture.
These CPU’s introduced the SSE2 & SSE3 Instructions set to accelerate calculations, transactions, media processing, 3D graphics, games etc. They also integrated Hyperthreading – that makes 1 Physical CPU works as 2 Logical & Virtual CPU’s.
It also came in two other versions
- Celeron (Low end – for Desktops/Laptops)
- Xeon (High end – for Workstations/Multiprocessor Server)
It was complemented by Pentium D & Pentium Extreme Edition Dual core CPUs.
(Intel’s later Itanium architecture was developed based on this processor.)
Read more about Intel i786 here

AMD introduced AMD K7 in 1999. It was brand named Athlon.
Read more about AMD K7 here

NOTE: Packages that are compiled for i786 architecture, is compatible with i786 architecture only.