fbpx
Arm booth logo from MWC 2019

When reading our coverage of SoC launches you have probably come across the term “custom CPU core,” especially when reading about Apple’s silicon. But what exactly is a custom core? Why do people make such a fuss about them? And, who designs them? Well, let’s find out!

Why Arm is so important for smartphones

All Android smartphones and all Apple iPhones use CPUs based on the Arm Instruction Set Architecture (ISA). An ISA defines the instruction set and outlines the design philosophy behind that instruction set. Most PCs use the x86-64 ISA, which is the 64-bit version of Intel’s original 32-bit ISA found in processors from the 1980s, such as the 80386 and 80486. AMD created the 64-bit version and released its first x86-64 processor in 2003. Smartphones, on the other hand, use the Arm ISA. Most smartphones in use today are built on Armv8, with newer chipsets moving to the latest Armv9 version.