X86 vs ARM
AMD and Intel have the x86 CPU market largely sewn up – but that isn’t the only platform in town. The major alternative is the ARM architecture, originally developed in 1985 by Cambridge’s Acorn (the story, and that of 19 computers from the 1980s, is told in our editor’s book, The Computers
That Made Britain; see pcpro.link/britain).
ARM chips embody a different philosophy to x86. They use the principles of reduced instruction set computing (RISC), prioritising simplicity and efficiency rather than chasing performance by building complex instructions and extensions into the core. ARM also pioneered the “big. LITTLE” chip format, which combines low and high-power cores in a single package – the former to keep the device ticking over when demand is low, and the latter to fire up for big computing tasks and go back to sleep afterwards.
While ARM chips have rarely been the fastest, their design has made them affordable and power-efficient compared to their CISC (complex instruction set) rivals: there’s a reason why nearly every smartphone and tablet has been built on ARM architecture. If it’s not a household name, that’s because ARM doesn’t make the chips itself. Rather it licenses its designs to manufacturers for use in chips such as the Nvidia Tegra, Samsung Exynos and Qualcomm Snapdragon.
The ARM approach has been so successful that it’s starting to encroach into traditionally CISC-dominated markets. We’re not just talking about Apple’s M1 CPU: Microsoft tried to bring Windows onto ARM back in 2012 with the original Surface tablet, and had another go in 2019 with the ARM-based Surface Pro X.
These ventures weren’t unequivocally successful. Windows RT died because it couldn’t run x86 desktop apps, while the latest ARM edition of Windows 10 can run regular Windows programs, but has to do so through emulation, which drags down performance.
Even so, Microsoft hasn’t given up. It’s reportedly working to ensure that Windows 11 runs as smoothly on ARM as it does on x86, while Qualcomm – which produced the ARM-based chips for the Surface Pro X – has pledged that its next range of laptop processors will outperform the Apple M1. In short, don’t take it for granted that your next Windows PC will be running on x86.