
RISC-V is the most important new instruction set architecture (ISA) that you are probably hearing for the first time. Don’t worry. Here you will learn:
- What is RISC-V?
- Why is it important?
- In what devices will we see RISC-V ISA? Computers, smartphones, embedded devices, or other types?
- Who will benefit and who will suffer from this new RISC-V?
There are many questions about this new tech, so let’s see.
What is RISC-V ISA?
The RISC-V (pronounced “RISC FIVE”) is an open-standard instruction set architecture (ISA) that offers free and versatile alternative to proprietary ISAs like x86, and ARM. RISC stands for Reduced Instruction Set Computing which means that it has fewer streamlined instruction, in comparison to Complex Instruction Set Computing (CISC) like x86.
The ISA is how the software is encoded and is basically the language that a processor understands. It is the translator that receives high-level code and outputs CPU instructions. Each instruction is an understandable command for the processor.
What separates it from the rest is that nobody needs to pay a fee to use it, so it is easier to start developing RISC-V hardware, and cheaper. Compare it to x86, which is owned by Intel and only Intel and AMD can use it, and ARM, which licenses its ISA and processor designs, you can see that it could be a very attractive offer.
A Brief history
The RISC-V history begins in 1980 when the term RISC was first introduced. The RISC ISA is a simplified set of instructions – a lot fewer than CISC (complex instruction set computer). Each of the instructions needs to accomplish less per data memory cycle, in comparison with the CISC.
The popular ISAs ARM and DLX were based on the original RISC.
On this basis, the scientist Krste Asanovic from Berkeley University in California started a “small summer project”. The goal is to create a modern open ISA, that anyone in the world can freely use. This work gave birth to the first version called Berkeley RISC in 2010. Later in 2014, the 5th version of it was named RISC-V.
Krste’s team published the RISC-V under a BSD license, together with several CPU designs, which allow other companies to use them and build their own implementation. The 3rd parties can create free, open-source, closed-source the way they desire.
Something important that we need to mention is that if some company uses RISC-V to design a chip, it does not need to publish its source code. So, a company like ARM can design a processor, license the design and sell it without any problems.
There is open-source and closed-source RISC-V hardware.
The Role of RISC-V International
To create a stable, standardized ecosystem around the new ISA, and prevent fragmentation, the RISC-V Foundation was created. It manages and maintains the documentation. The Foundation moved to Switzerland in 2019, so it won’t be affected by the U.S. and China trade tensions or any other global conflict. From 2020 it was renamed RISC-V International.
Why does RISC-V matter?
RISC-V is a disruptive technology that brings the following benefits:
- Reduced complexity – 47 base instructions and modular ISA.
- Free design – the 3rd parties are free to design their SoC the way they desire.
- No licensing fees – companies can develop processors freely, which reduces costs.
- RISC-V can lead to a new open era of computing that will lead the chip innovation in the future.
Can RISC-V run any popular OS?
The RISC-V ISA is not really targeting the computer or mobile market right now. Today, almost everything has a chip inside – IoT devices, wearables, cars, electric appliances, machines, etc.
But, yes, RISC-V can power a system with a Linux distribution. Back in 2021, there were just two companies that offered computer configurations with RISC-V processors. They were SiFive and Andes Technology.
Now, you can find SiFive HiFive Unleased, SiPeed LicheeRV, DC-ROMA RISC-V Laptop II, BeagleV, LicheePi 4A, and more.
These devices can run one of the following operating systems: Ubuntu, Debian, Fedora, and openSUSE. Android support is also available although it is not perfect yet.
Windows 11 support is still missing but will change in the future if the architecture continues to grow.
Are there other ISA designs?
Yes, there have been quite a few ISA designs:
- 6502 (8-bit)
- Z80 (8-bit)
- 68000 (32-bit)
- x86 (32-bit and 64-bit)
- Alpha (64-bit)
- MIPS (32-bit and 64-bit) – Under Wave Computing’s MIPS Open program is royalty-free. But it requires a compliance certificate.
- Itanium (64-bit)
- Power (32-bit and 64-bit)
- SPARC (32-bit and 64-bit) – open-source. But it requires a compliance certificate.
- VAX (32-bit)
- ARM (32-bit and 64-bit)
What you can see is that most of the processors’ architecture is not open-source, nor royalty-free. A few companies control the intellectual properties and no matter what device another company is producing – PC, tablet, mobile phone, IoT, wearables, cars, electric-domestic appliances, or anything with a chip, a fee must be paid.
This is why it is very important to look at the free and open-source ISA. It might lower the price of future tech items and keep the competition busy with innovations.
x86 ISA
The x86 processors have been the dominant type of CPU for computers for a long time. Still, when you are searching for a new computer, cloud server, or a dedicated one you will see Intel’s or AMD’s options, and they are both using processors with x86 architecture.
The x86 ISA is a product of Intel and it was first used for the 8086 microprocessor. In the more than 50 years since it was introduced, there has been a lot of development, adding new extensions and software.
For many years x86 was the way to go, without any significantly important option on sight. But there came ARM.
The newcomer ARM is a company that creates, and licenses designs for CPUs and GPUs.
It dominates the mobile market, and it is heading towards the PC market too. There are many Chrome OS computers, Linux computers, Windows, and even Apple devices.
Apple decided to choose ARM as the only ISA it wants to use in the future, abandoning the x86 ship. This clearly shows how the market is changing.
ARM ISA
The ARM architecture is a RISC architecture, similar to RISC-V, but it is not open-source. The previous name of it was Advanced RISC Machines. The intellectual properties are owned by Arm Ltd.
The company is charging a license fee for their designs like A78, Mali GPU, etc.
But also, they allow companies to modify them and create their cores like Apple, Microsoft, Qualcomm, etc.
Currently, no matter if you are using an Android or iOS smartphone, you have an ARM chip inside.
The advantage that it has over RISC-V is that it is a mature platform already. There is a lot of software and new extensions that make it very interesting for different industries. Just see the OS variation that it can run: Windows 11, Windows 10, Ubuntu, Debian, Fedora, FreeBSD, FreeRTOS, Android, Chrome OS, Tizen, Windows 10 IoT Core, etc.
Arm costs license fee, so RISC-V can compete in the different price segments, where the low cost is more important than the performance.
RISC vs CISC
The two most popular ISA types are RISC and CISC. The CISC is the one that Intel and AMD use in their computer processors and the RISC is used for all kinds of electronics and mobile devices.
RISC emphasizes software, while CISC emphasizes hardware.
RISC uses single-clock instruction as opposed to multiple-clock complex instructions on CISC.
Register to register “Load” and “Store” are independent instructions vs memory to memory “Load” and “Store” are a part of instructions.
Low cycles per second, large code sizes, and more RAM needed vs small code sizes, high cycles per second with less RAM needed.
A small number of instructions vs many instructions.
Table of comparison
Feature | RISC (e.g., RISC-V, ARM) | CISC (e.g., x86) |
Instruction Complexity | Simple, few instructions | Complex, many instructions |
Clock Cycles per Instruction | Single cycle | Multi-cycle |
Memory Usage | More RAM required | Less RAM required |
Power Efficiency | High | Lower |
Performance Focus | Optimized for efficiency | Optimized for performance |
Future of RISC-V
The main challenge in front of RISC-V is fragmentation. If there are many different RISC-V ISAs, that are developed by different companies (Google, Nvidia, Western Digital, Alibaba, and more), that will be a huge problem. This is why the RISC-V foundation was created to orientate the project towards the right direction of standardization.
The RISC-V is still too new. It is not a mature platform which means that there are not enough developers, or software already available. Yes, it is growing very fast, but it hasn’t guaranteed its place on the chip market in the long term. Or at least not as the main chip of a device.
What we can expect in the near future (2026-2027) is to see RISC-V inside mainstream consumer electronics. We can see products from companies like Qualcomm, Alibaba, and Samsung like laptops, tablets, TVs, IoT, and wearables with RISC-V chips.
RISC-V has a huge opportunity in China. Due to the friction between the USA and China, it might end up as an ARM vs RISC-V war. The USA can control all US companies, including Nvidia and Intel. If this happens, China might see RISC-V as their only choice of action.
This architecture is suitable for AI, automotives, and even aerospace, so we will continue to hear about it. It will probably find use in lower-cost AI chips for various tasks.
It is interesting to see, when will RISC-V expand into High-Performance Computing (HPC) and AI. Yes, the performance is still lagging behind, but we can see custom accelerators, tailored to specific workloads, that can provide good results.
Conclusion
RISC-V is growing rapidly, and it will be one of the most significant technologies soon. Where exactly it will end, it is still not clear to see. The advantage of a free ISA is great, but the fact that the processors are still lagging behind ARM in terms of performance is important. Yes, ARM costs, but it also delivers. Just see how good Apple Silicon chips are going.
Still, most probably we will see many devices of any size with RISC-V chips inside. It might happen without you even noticing.