Microprocessors are at the heart of many electronic devices. They are tiny computers in the simplest form. They generally do not rely on operating systems and handle simple tasks such as reading sensors, controlling LEDs and displays, and handling simple computations.
What is RISC-V?
RISC-V is an open-source instruction set architecture (ISA) designed for efficiency and versatility in computing devices. RISC-V is freely available for anyone to use, modify, and implement without licensing fees. Its design emphasizes simplicity, making it easier to build processors with varying performance levels and specialized applications. RISC-V's modular structure allows for customization, enabling tailored solutions for diverse computing needs, from embedded systems to supercomputers. Its widespread adoption stems from its flexibility, cost-effectiveness, and scalability, making it a preferred choice for industries ranging from consumer electronics to data centers. As a result, RISC-V fosters innovation by democratizing access to processor designs and promoting collaboration among developers and researchers worldwide.
What is ARM?
ARM, which stands for Advanced RISC Machine, is a type of processor architecture widely used in smartphones, tablets, and other embedded devices due to its energy efficiency and performance. It employs a Reduced Instruction Set Computing (RISC) approach, streamlining instructions for faster processing and lower power consumption. ARM processors are also prevalent in various other applications, including automotive electronics, smart home devices, and industrial machinery. Its versatility and scalability make ARM an ideal choice for diverse computing needs, from low-power IoT devices to high-performance computing systems. Furthermore, ARM's architecture is licensable, allowing companies to customize designs for specific applications, leading to a broad ecosystem of ARM-based products tailored to different market segments.
RISC-V vs. ARM
RISC-V and ARM are both instruction set architectures (ISAs) commonly used in the design of computer processors. While they share some similarities, they also have several differences. Here's a list of some key differences between RISC-V and ARM:
Modeling & Architecture: Historically, ARM has dominated the microprocessor market, from low-power devices to high-performance processors. This was mainly due to its licensing model, which allowed various companies to license IP and customize it for their own applications. Additionally, ARM has developed multiple processing families, such as the Cortex-A for high-performance applications, the Cortex-R for real-time applications, and the Cortex-M for energy efficiency applications − with each family becoming the unofficially recognized performance standard for various applications.
On the other hand, it was ARM’s proprietary modeling that inspired the RISC-V architecture. Researchers at Berkeley began the architecture as an open-source alternative to promote greater innovation in technology. It has since been embraced by many big tech companies such as Google and Nvidia.
ARM has well-established software and hardware that can help companies accelerate the development cycle. It also has an extensive line of choices with mature feature sets. On the other hand, RISC-V’s architecture offers flexibility and a level of customization that cannot be had with ARM devices. Taking into consideration raw performance, ARM will outperform any RISC-V processors. And although ARM continues to maintain its lead in performance, RISC-V has proven to offer higher computation densities. This means you will get a smaller chip for the same performance. This can prove advantageous in many applications, such as wearables like smart watches. It is worth noting that there is currently research and effort taking place to improve the performance of RISC-V processors, and how well their performance will stack up against ARM in the future will highly depend on the outcome of these efforts.
Openness and Licensing: RISC-V and ARM are both instruction set architectures (ISA). However, where they differ, primarily, is that RISC-V is an open-source ISA, whereas ARM is a proprietary ISA.
Instruction Set: RISC-V has a fixed instruction set architecture with a base integer instruction set and optional extensions for features like floating-point arithmetic, atomic operations, vector processing, etc. ARM has multiple instruction sets, including ARMv7, ARMv8, and various extensions like NEON for SIMD (Single Instruction, Multiple Data) operations.
Flexibility and Customization: RISC-V allows for more flexibility and customization because it is open, enabling designers to tailor the ISA to their specific needs. ARM, while offering some level of configurability through its extensions, has limitations due to its proprietary nature.
Ecosystem and Industry Adoption: ARM has a well-established ecosystem with a wide range of processors, development tools, and support from various vendors. It's widely used in mobile devices, embedded systems, and increasingly in servers and data centers. RISC-V's ecosystem is still growing but has gained significant traction, particularly in academia, research, and startups. It's also gaining attention in IoT, edge computing, and some server applications.
Performance and Power Efficiency: ARM has made energy efficiency a key focus area throughout its time, dominating the market. They already offer options that focus on power efficiency and ease of use for low-power devices. Furthermore, they have options available with hardware floating point and DSP extensions that are suitable for higher-end applications such as cell phones.
There also happens to be a large array of power-saving features available. Some of these include dynamic voltage and frequency scaling, which allows the processor to decrease or increase the voltage and clocking of the chip depending on real-time requirements. RISC-V, on the other hand, allows for a smaller silicon footprint, which will give it a power consumption advantage. In addition, the fixed 32-bit instruction format and 16-bit compressed instruction extension can help lead to more power-efficient code implementation. Overall, while RISC-V offers the potential of a lower power-consuming device, it is not there yet. Work and time still have to be invested into RISC-V before it can begin to take market share from ARM.
Cost and Accessibility: Implementing RISC-V cores can potentially be more cost-effective for companies due to the lack of licensing fees associated with ARM. ARM cores often require licensing fees, which can increase the cost of production for devices utilizing ARM architectures.
Instruction Encoding: RISC-V uses a fixed-length instruction encoding, simplifying decoding logic. ARM employs a variable-length instruction encoding, allowing for more compact code but potentially more complex decoding logic.
Is RISC-V or ARM Better?
In conclusion, RISC-V is gradually gaining traction in the industry. Currently, it works very well for small applications and can even offer an advantage when compared to its ARM counterpart. Its open-source architecture has attracted a growing number of large tech companies, and its ecosystem is expanding. However, ARM continues to dominate the market with a more mature and established product. It has a wide line of processors to support various applications. Additionally, its tools and hardware are stable, well-supported, and well-documented. The abundance of devices on the market also ensures it will be a trusted solution by companies for many years to come.