They're both RISC. So why is one of them rewriting the rules of the chip industry? The real differences — open vs licensed, ISA philosophy, ecosystem — and an honest take on whether RISC-V will challenge ARM.
Both RISC-V and ARM are RISC architectures — load/store machines with simple, fixed-style instructions, lots of registers, and the design philosophy from Day 1 of our ARM course. Line up a basic ADD or LDR and they look like cousins. So the rivalry isn't really about the instructions.
The real difference is who owns the rulebook — and that single fact ripples through cost, customisation, ecosystem and geopolitics.
An open standard (born at UC Berkeley, now stewarded by RISC-V International). Anyone can implement it, extend it, and ship it royalty-free. No licence fee, no permission needed.
ARM Holdings licenses its architecture and cores. Companies pay an upfront licence fee plus royalties per chip. In return they get mature, optimised, verified designs and support.
Think of it as Linux vs Windows, but for CPU architectures. One is an open commons anyone can build on; the other is a polished commercial product you pay for. That's the heart of the whole debate.
RISC-V is deliberately minimal and modular. You start with a tiny base integer ISA (RV32I or RV64I) and bolt on only the extensions you need:
RV32IMC; a big application core adds F, D, V and more.ARM is rich and mature. Its ISAs (A32/T32 and the 64-bit A64) bring decades of refinement — a powerful barrel shifter, historically conditional execution, advanced SIMD (NEON/SVE), security and virtualization features — as a more uniform, ready-made whole.
RISC-V's modularity means freedom and minimal silicon — but also potential fragmentation (many custom variants). ARM's richness means consistency and capability out of the box — but less freedom and a price tag.
| Aspect | RISC-V | ARM |
|---|---|---|
| License | Open, free, royalty-free | Proprietary — fee + royalties |
| Origin | UC Berkeley (2010), RISC-V Intl. | Acorn/Arm (1985), Arm Holdings |
| ISA style | Small base + optional extensions | Rich, mature, more uniform |
| Customisation | Add your own instructions freely | Limited (some custom on licences) |
| Ecosystem | Growing fast, less mature | Vast & mature (tools, OS, software) |
| Maturity / scale | Newer; billions in MCUs/embedded | ~300B+ chips shipped, decades proven |
| Conditional exec | No general predication (branches) | Predication (A32) + CSEL (A64) |
| Compressed code | C extension (16-bit) | Thumb / Thumb-2 |
| Vectors | V extension (RVV) | NEON / SVE |
| Strong in | MCUs, custom/in-house cores, research | Phones, laptops, servers, most MCUs |
This is where ARM's lead is biggest — and it's not the ISA, it's everything around it. Decades of compilers, operating systems (Linux, Android, RTOSes), debuggers, libraries and battle-tested software assume ARM. Hundreds of billions of ARM chips have shipped. That momentum is enormous.
RISC-V's ecosystem is younger but growing remarkably fast: GCC/LLVM support it, Linux runs on it, and tooling improves every year. The gap is closing — fastest at the low end (microcontrollers) and in custom silicon, slowest at the high-performance, software-heavy end.
• Microcontrollers & deeply embedded
• Custom / in-house cores (storage controllers, the control core inside AI accelerators, etc.)
• Research & education (free, open, hackable)
• Sovereignty — countries/companies avoiding licensing dependence
• Smartphones (essentially all of them)
• Laptops (Apple M-series) & servers (Neoverse)
• Anything needing a mature software stack fast
• Most microcontrollers today (Cortex-M)
A telling pattern: many companies use both — ARM application cores running the OS, with small RISC-V cores sprinkled in for housekeeping and custom tasks where paying royalties on a tiny core makes no sense.
The honest answer: probably not "replace" — but it will keep taking share.
The case for RISC-V's rise: zero licensing cost, total freedom to customise (huge for AI and domain-specific chips), no single vendor dependence, and rapidly maturing tools. Geopolitics adds fuel — an open ISA can't be export-restricted the way licensed IP can, so regions seeking technological sovereignty are investing heavily.
The case for ARM's staying power: a colossal, mature ecosystem; proven high-performance cores; a deep software base; and the simple fact that switching architectures is expensive and risky. ARM isn't standing still either.
Expect coexistence, not a knockout. RISC-V is already winning in microcontrollers, custom/in-house cores and academia, and is climbing toward higher performance. ARM remains dominant in mobile and high-performance computing for the foreseeable future. The interesting story isn't "who kills whom" — it's that, for the first time in decades, there's a credible open alternative, and that competition benefits everyone.
Both are RISC ISAs; the big difference is the business model — RISC-V is open and royalty-free, ARM is licensed IP. RISC-V is modular; ARM is richer and more mature.
Neither is universally better. RISC-V wins on openness, cost and customisation; ARM wins on a vast mature ecosystem and proven high-performance cores.
Not wholesale, and not soon — but it keeps gaining share in MCUs, custom cores and research. Expect coexistence.
The ISA is free to implement and extend. Building a real chip still costs money — cores, tools, IP, verification and fabrication.
Learn the architecture hands-on: Build a RISC-V CPU from Scratch · ARM Architecture from Scratch · SHAKTI — India's open RISC-V chip · VLSI Hub