Simple means efficient
ARM is a RISC architecture: fewer, simpler instructions than x86. The chip is therefore smaller and uses less energy. When the first ARM1 was switched on, it worked even though it was not properly powered; leakage current was enough.
Licences instead of factories
Arm Holdings does not make chips. It sells design licences to companies such as Apple, Qualcomm, Samsung and MediaTek. That is why ARM is everywhere: phones, tablets, cars, routers and the Raspberry Pi.
Apple M1 and beyond
In 2020 Apple stopped using Intel and introduced its own M1 chip. Laptops were faster, cooler and lasted a full day on battery. More generations followed. Since 2024 ARM has also been spreading in Windows laptops (Qualcomm Snapdragon X).