Why Different Types of Processors?
Although it might seem like all processors only differ by core count, there's a wide variety of architectures that cater to specific device requirements.
The needs of a home Router, in terms of power and efficiency, are not the same as those for a mobile phone or a high-performance server. Since the early days of computing, multiple architectures based on two fundamental types have emerged to address specific use cases.
2 Types of Architectures
CISC (Complex Instruction Set Computing):
- Key Features: Executes complex operations with a single instruction.
- Advantages: Greater flexibility for advanced tasks.
- Disadvantages: Has internal complexity several orders of magnitude higher than RISC processors, increasing development and production costs.
RISC (Reduced Instruction Set Computing):
- Key Features: Breaks down operations into simpler, more efficient steps. Most instructions occupy a single processor cycle.
- Advantages: Much more efficient than CISC processors due to its simpler internal design. Also typically has a simpler memory access system (RAM) compared to architectures like x86.
- Disadvantages: Since the instructions are simpler, the running program needs more instructions to complete tasks.
Current Major Architectures
x86
Description: A CISC architecture, x86 processors are most common in Home PCs, Workstations, Laptops and Servers. Developed by Intel for 16 and 32-bit versions (x86) and by AMD for the 64-bit version (x86-64/AMD64), it's characterized by its power per core and diverse implementations, from simple processors like the Intel Pentium to AMD EPYC with 128 cores used in data centers.
Examples:
- All types of PCs
- Home NAS devices
- Most cloud provider VMs (Azure, AWS)
- Servers and data centers (Intel Xeon and AMD EPYC)
Peeker
The STS (Space Transport System) from the NASA, better known as the space shuttle, used Intel 486 processors in its cockpit computing systems.
ARM
Description: Stands for Advanced RISC Machine, ARM architecture is the most widely used overall, across all types of devices. It's only surpassed by x86 in home PCs and servers, while it dominates integrated devices from mobile phones to routers, cars, planes or robots.
This architecture is significantly simpler and more affordable (generally) than x86, with implementations focusing on efficiency. ARM Holdings licenses other companies like Qualcomm or Apple to create their own ARM designs, increasing the supply of these processors compared to Intel/AMD in x86.
Examples of devices:
- Mobile phones and Tablets
- Apple Silicon and Microsoft Surface laptops
- Single Board Computers (SBC) like Raspberry Pi
- NVIDIA Blackwell hybrid CPU+GPU systems
- Microcontrollers such as Raspberry Pi Pico 2
- Consoles like PlayStation 2 & 3 or Nintendo Switch
- Car and motorcycle ECUs
- Sensors, actuators and all types of integrated systems
RISC-V
Description: Developed at the beginning of the 2010s, RISC-V stands out with a fixed instruction set even smaller than ARM, and more efficient. It has no development restrictions, allowing anyone to design and produce processors based on this architecture. Currently, there are various RISC-V processors from microcontrollers to experimental servers with 64 cores.
Examples of devices:
- ARM cores in Raspberry Pi Pico 2 (hybrid ARM/RISC-V)
- Experimental server processors
PowerPC
Description: Originally designed at the end of the 1990s by IBM and Motorola for use by Apple, it's still used in integrated devices and IBM servers.
Examples of devices:
- Original Apple Mac series, like the first iMac and Mac Pro
- Consoles like Xbox 360, Wii, and Wii U
Conclusion
This article explores modern processor architectures, demonstrating that beyond core count, each design is optimized for specific needs. We've analyzed CISC (executing complex operations in a single instruction but more expensive) and RISC (more efficient and economical though requiring more steps), as well as concrete architectures like x86 (dominant in PCs), ARM (predominant in mobile devices) and RISC-V (emerging yet experimental). Each type excels for its purpose, from servers to video game consoles, helping us understand why different processors are used for varied technological needs.