Although you've probably "x86" on download pages for certain apps or maybe on some computer settings pages, you might not know exactly what it is beyond just being a computer thing. Well, behind that, those three characters are one of the most important pillars in the world of computing and silicon and have been for generations. It's the reason why the best (and only) desktop CPUs are made by Intel and AMD. This is the history of the x86 architecture and everything you need to know about it.

x86: A venerable and critically important instruction set architecture

A render of a Ryzen 7000 CPU.

x86 is an instruction set architecture (ISA), which is essentially the design of the most basic components of a processor. The ISA is a critical factor in what kind of software can run on a processor; if code can be run in a very efficient, native way or with an inefficient workaround (such as needing to use addition over and over instead of multiplication); and what a processor has to include in order to be built on a particular ISA.

For x86, the technical details aren't super important. Rather, the companies behind x86 are what make this ISA so important. Intel developed the x86 ISA in the late 1970s and built an empire out of it (albeit one going through some serious decay now), and to this day, Intel still makes brand-new x86 CPUs using an ISA that's almost 50 years old. AMD, Intel's principal rival in CPUs, also makes x86 processors, and although AMD has historically been quite small compared to Intel, they're now of comparable size and importance.

The crucial thing to understand about any ISA is that x86 software can run on any x86 CPU, even if they're really different. Intel and AMD CPUs are as different as they can be, but they still use x86 architecture and, thus, can run the same software. You'll often see CPU designs like Raptor Lake and Zen 4 referred to as architectures, but technically they're micro-architectures because they're not nearly as fundamental as an ISA.

A brief history of x86

An Intel 11th Gen Rocket Lake CPU.

The x86 architecture was introduced with Intel's legendary 8086 processor, a cheaper variant of which was the 8088 that powered IBM's equally legendary Personal Computer in 1981. The success of the 8086 and 8088 CPUs is what kickstarted not only Intel's dominance in computing but also the prevalence of the x86 ISA. AMD first started manufacturing x86 chips for Intel to use in the Personal Computer, but eventually, Intel tried to cut AMD out of the picture, which led to a legal battle between the two companies. In 1995, AMD won the right to make its own x86 chips.

As consumer, business, and enterprise demand for computers grew from the 1990s onwards, both Intel and AMD grew in size, as did the complexity of x86 CPUs. This created an opening for AMD to challenge Intel by designing superior CPUs. By the mid-2000s, AMD had not only taken substantial portions of the desktop and emerging server markets, but it had also invented the 64-bit extension of x86 (termed AMD64 or x86-64), which basically enabled handling larger numbers. This essentially killed Intel's brand-new 64-bit ISA and Itanium server chips, one of Intel's worst CPUs ever.

The crucial thing to understand about any ISA is that x86 software can run on any x86 CPU, even if they're really different.

From the late 2000s on, Intel has generally been more important than AMD, though since 2017, AMD has been steadily increasing its market share in PCs and servers, and now Intel isn't all that much bigger. Additionally, both Intel and AMD have attempted to expand x86 to other areas such as consoles, mobile phones, and Internet of Things (IoT) devices. For many years, Intel had been particularly focused on breaking into the smartphone market, which has been traditionally dominated by ARM CPUs, but eventually failed for a variety of reasons. AMD made no serious plans for smartphone processors.

Gaming consoles are perhaps the only safe bastion for x86 outside of PCs and servers. The first x86-powered console was the original Xbox, which used a Pentium III CPU, but it would be the only x86 console for some time. PowerPC chips from IBM were subsequently used for the PS3, Xbox 360, Wii, and Wii U. However, for the PS4 and Xbox One, both Sony and Microsoft went to AMD to create a custom x86 chip for their new consoles. The current generation PS5 and Xbox Series X/S also use AMD chips, as do handheld gaming PCs like the Steam Deck and ROG Ally.

The future of x86 and the challenges it faces

Intel's 12th-gen mobile CPU next to Apple M1 chip

While both Intel and AMD use x86, and they're very much rivals, there are other challengers that seek to dethrone x86 in general. There are actually a lot of different ISAs out there, but the two most important alternatives to x86 are Arm and RISC-V, both of which want to dismantle x86's hegemony over PCs and servers. And we're not just talking about two companies here, but hundreds.

Although Arm and RISC-V are very different and are also in an intense rivalry, they both offer a basic CPU design to partner companies, and those companies can, in return, make their own CPUs using those ISAs. Notable producers of Arm chips include Apple (which recently made the switch from Intel to its own Arm processors for its silicon), Samsung, and Google. Meanwhile, RISC-V is mostly used in industrial applications and as companion processors in devices like FPGAs and hard drives, though RISC-V does have ambitions for the whole CPU market.

If Arm and RISC-V want to challenge Intel and AMD in their PC and server strongholds, new software will have to be written, and that will take time.

The one key advantage that x86 has in all of this is that x86 software can't run on non-x86 CPUs. If Arm and RISC-V want to challenge Intel and AMD in their PC and server strongholds, new software will have to be written, and that will take time. There are workarounds like Apple's Rosetta 2, which translates x86 applications to Arm on the fly, but it's not perfect. The difficulty of introducing a new ISA to an already developed hardware-software ecosystem is actually the very same thing that killed Intel's smartphone plans.

x86 has been more or less unchanged in two decades, with the last major update being AMD's 64-bit extension. However, Intel has been floating the idea of cutting all the non-64-bit stuff in x86 to create the tentatively named x86S architecture. This would theoretically result in better performance and efficiency, and although not having 32-bit support was a bad idea back in 2003, these days pretty much all hardware is 64-bit.

It's hard to say what will happen to x86 and whether it will lose against Arm and RISC-V in the long run, continue to dominate in PCs and servers, or even transform itself to head off competitors. Whatever the future holds, it's certain that it will take a long time for anything new to happen. x86 is here to stay, at least for the time being.