CPU architectures
While there are many different manufacturers of CPUs, including Intel, AMD, and, more recently, Apple, there are two main types of CPU architectures that you’re likely to come across: Intel (x86 and x64) and ARM.
Intel (x86 and x64) Architecture
Intel’s x86 and x64 architectures have been the backbone of personal computers and servers for many years. The terms x86 and x64 refer to the instruction set architectures that these CPUs use.
The x86 architecture, used in 32-bit processors, has a complex instruction set computer (CISC) design, which means the CPU can perform complex operations with single instructions. This was especially useful in the early days of computing when memory was scarce. You were able to do more with fewer instructions.
However, as technology advanced, so did the need for more powerful computing capabilities. This led to the introduction of x64 (or x86-64) architecture, used in 64-bit processors. It’s an extension of x86, allowing for more memory and better performance. Intel and AMD processors like the Intel Core i7 or AMD Ryzen 7, found in many desktops and laptops, use this architecture. These CPUs are powerful and great for heavy-duty tasks like gaming, video editing, and running complex software applications.
ARM Architecture
On the other hand, ARM architecture, which stands for Advanced RISC Machine, uses a reduced instruction set computer (RISC) design. This means the CPU performs simpler operations, and complex tasks are broken down into multiple simpler instructions.
ARM CPUs, from the beginning, were designed with energy efficiency and cost-effectiveness in mind. This makes them perfect for mobile devices like smartphones and tablets, where battery life is crucial. So, with the advent of mobile phones and tablets, ARM became much more common. If you’ve used an iPhone, an iPad, or an Android device, you’ve used a device powered by an ARM-based CPU.
Recently, ARM processors have started making their way into laptops, with Apple’s M1 and M2 chips leading the way. These chips offer excellent performance while consuming less power and generating less heat than their Intel counterparts, leading to longer battery life.
Key Differences
So, one of the fundamental differences between Intel and ARM CPUs, or between CISC and RISC, lies in their architecture and design philosophies. The complex instruction set of a CISC design allows for a broad range of capabilities and high performance, ideal for resource-intensive applications. However, the chips need to be larger and more complex to do this.
On the other hand, RISC is simpler and more energy-efficient, making it ideal for portable devices. And while traditionally less powerful than their Intel counterparts, the gap is quickly closing.
There’s another important difference: software written for one architecture won’t work on the other without some form of translation or emulation. The instructions for one architecture are completely different from the ones for the other. This is why some older apps don’t work on new Macs with the ARM chip, as those apps were written for Intel’s architecture. The older apps can still work, but they require a small emulator that translates the instructions from Intel to ARM. This extra layer, of course, will require extra energy and make the old programs a bit slower to run.