While RISC-V vs. ARM might seem like two completely different things, they are, in fact, distinct implementations of the same design concept. In this article, we take a closer look at them – if you feel that you’d like to learn more about RISC-V vs. ARM, then we encourage you to read on.

RISC-V vs. ARM – The Key Differences

We will begin with the main differences between RISC-V vs. ARM.

RISC-V is an instruction set architecture standard run under an open license. Its main advantage is the flexibility that it offers – hardware implementations allow you to shape it for specific needs, like power efficiency, instruction density or performance, and most importantly – to extend the instruction set.

ARM or Advanced RISC Machine is also an instruction set architecture based on RISC. It can be dated back as far as to the 1980s and has undergone numerous evolutions and changes since. Most importantly, it’s the most common ISA used in embedded systems.

RISC-V vs. ARM Compared

With this short introduction behind us, let’s take a glance at a bit more detailed comparison of these two from different angles and performance indicators:

  • RISC-V vs. ARM: performance – In terms of performance, RISC-V and ARM are worthy opponents. The verdict obviously depends on the particular processor models, but you can get satisfying units in both architectures.
  • RISC-V vs. ARM: power efficiency – Knowing what embedded systems are, you should be aware that power usage is one of the most critical factors in determining the right technological solutions for such devices. When it comes to these two architectures, RISC-V is quite power-efficient due to its modular design; however, it’s ARM’s dynamic voltage and frequency scaling that provides true energy efficiency.
  • RISC-V vs. ARM: ecosystem and support – ARM, as the older brother in this pair, offers stability, proven tools, and widespread adoption within numerous industries. While it might leave RISC-V at a slight disadvantage, the younger of these two architectures is growing rapidly and attracting key players like Google or NVIDIA, so it’s likely to soon outgrow ARM, at least in terms of ecosystems and support.

So, which one of these ISAs is better? To be honest, it usually doesn’t matter.

Why Don’t the ISA Differences Matter Anymore?

With RISC becoming the dominant model of ISAs, and all of them having their advantages, the significance of choosing the right ISA has dropped. The transistor count no longer matters, especially when compared to caches, instruction-level parallelism (pipelining, branch prediction, speculation), data-level parallelism (vector instructions, GPU), or thread-level parallelism (SMP, NUMA).

It doesn’t mean that there are no occurrences when you should pay attention to the type of ISA, but purely that in most cases, there are much more important factors to consider.

When Does the ISA Matter?

So, what are these rare situations in which you should pay attention to the type of instruction set architecture? It can happen in four cases:

  • Money is vital – Sometimes, licensing costs for SoC manufacturers will vary so much that you will simply prefer one ISA over another. But, the truth is that in such cases, you usually still don’t make a choice with regard to any technical aspects, so we could still say that the differences don’t matter.
  • Features – Another situation in which you might pay slightly more attention to different ISAs is when you need a specific feature, not available in all of them. Whether it’s compressed instructions or a particular SIMD opcode, you will likely need to go with architecture that offers you the functionalities in demand.
  • Legacy software – Often, you don’t even get to make a choice. This is exactly the case with legacy software. In such situations, you might simply be forced to use a particular ISA since you wouldn’t be able to integrate any other architecture into your current system.
  • New, cutting-edge solutions – Different ISAs are like equally skilled runners in a race – they will draw in the end, though different runners might be in the lead on their way. The same is true for architectures – sometimes, a cutting-edge solution is first available only in a particular ISA, and you need to wait for it to be supported in the other architectures. In such situations, the choice of ISA matters – it depends on whether you wish to wait or want the support for the particular feature in your product right away.

What Matters More for You from a High-Level Perspective?

So, what’s more important than the choice between ARM vs. RISC-V? We would like to draw your attention to three particular elements:

  • IP core availability – The accessibility of intellectual property (IP) cores compatible with the chosen ISA to make the integration into SoC seamless.
  • Adaptation to technical needs – While “tailored to your needs” has become a marketing buzzword, the truth is that it’s exactly what you should look for – an architecture in line with the principles of your product.
  • Part availability – Finally, you should consider whether you can order the hardware elements for your embedded system. If not, perhaps you can change the concept and have more options when it comes to parts.

We Can Do It for You!

At Conclusive, we’re experienced in working with multiple RISC design-derived ISAs. This means that we can handle the low-level side of your product development no matter what choice you make. This way, you will be able to focus on your product in a platform-agnostic way!

You may also read: What is RISC and CISC Architecture & Their Differences