RISC-V vs ARM: Embedded Architecture

Why This Decision Matters Now

The processor architecture you choose for an embedded product locks you in for 5–15 years of product lifecycle. In 2026, this decision is more consequential than ever because:

1. RISC-V has reached production maturity. Over 10 billion RISC-V cores have shipped as of 2025. It’s no longer experimental — SiFive, Espressif (ESP32-C3/C6), Bouffalo Lab, and WCH are shipping production silicon.

2. ARM licensing costs are increasing. Arm Holdings’ IPO and subsequent business strategy have pushed licensing fees higher, particularly for IoT-scale designs where margins are thin.

3. EU digital sovereignty demands open architectures. The EU Chips Act’s €43 billion investment explicitly supports open-source hardware, and the European Processor Initiative (EPI) is building its HPC processors on RISC-V.

4. AI at the edge requires custom instructions. RISC-V’s extensible ISA lets you add custom AI acceleration instructions — ARM’s fixed ISA cannot match this flexibility. See Edge AI.

Choosing wrong means either overpaying for ARM licenses on a cost-sensitive IoT device, or underestimating the tooling maturity needed for a time-critical launch.

Architecture Fundamentals

What Makes Them Similar

Both ARM and RISC-V are RISC (Reduced Instruction Set Computer) architectures:

• Load/store architecture — memory access separated from computation
• Fixed-width instructions (mostly 32-bit)
• Large register files (32 general-purpose registers in both)
• Pipelined execution for high throughput

What Makes Them Different

Aspect	ARM	RISC-V
License model	Proprietary — pay per core or per chip	Open-source (BSD) — free forever
ISA extensions	Fixed by Arm Holdings (Neon, SVE, Helium)	Modular — add custom extensions freely
Instruction encoding	Variable (Thumb-2: 16/32-bit)	Clean fixed-width (32-bit base, 16-bit compressed)
Architecture versions	ARMv7-M, ARMv8-M, ARMv9 (complex versioning)	Simple: RV32I, RV64I + standard extensions (M, A, F, D, C)
Backward compatibility	Extensive (decades of legacy support)	Clean-slate design, no legacy burden
Custom instructions	Not permitted by license	Fully permitted and encouraged
Vendor lock-in	Tied to Arm Holdings’ roadmap and pricing	No single vendor dependency

RISC-V’s Modular ISA Explained

RISC-V’s key innovation is its modular design. You pick only the extensions you need:

RV32I     — Base integer (mandatory, 47 instructions)
  + M    — Integer multiply/divide
  + A    — Atomic operations (multi-core, RTOS)
  + F    — Single-precision floating point
  + D    — Double-precision floating point
  + C    — Compressed instructions (16-bit, reduces code size 25-30%)
  + V    — Vector operations (SIMD, AI acceleration)
  + B    — Bit manipulation
  + Zicsr — Control/status registers
  + Custom — YOUR custom instructions for your application

Example: A simple IoT sensor needs only RV32IMC (integer + multiply + compressed) — a tiny core using ~15K gates. A Linux-capable application processor needs RV64IMAFDC — a much larger core but still license-free.

This modularity is why RISC-V is particularly powerful when integrated into FPGAs — you can synthesize exactly the processor you need alongside custom hardware accelerators.

Head-to-Head Performance Comparison

Real Silicon Benchmarks (2026 Data)

Chip	Architecture	Core	MHz	CoreMark	CoreMark/MHz	Power	Price (1K qty)
STM32F407	ARM Cortex-M4	M4	168	566	3.37	150 mW	€6.50
GD32VF103	RISC-V (Bumblebee)	RV32IMAC	108	360	3.33	90 mW	€2.80
ESP32-C3	RISC-V	RV32IMC	160	407	2.55	110 mW	€1.20
ESP32-S3	ARM+Xtensa	Dual Xtensa LX7	240	1,181	4.92	310 mW	€2.50
STM32U5	ARM Cortex-M33	M33+TrustZone	160	651	4.07	40 mW	€5.80
BL616	RISC-V (T-Head E907)	RV32IMAFCP	320	1,050	3.28	120 mW	€1.50
CH32V307	RISC-V (RISC-V4F)	RV32IMAFCX	144	476	3.31	80 mW	€1.80
SiFive U74	RISC-V	RV64GC	1,500	8,200	5.47	2 W	€15+ (SoM)
NXP i.MX 8M	ARM Cortex-A53	A53 quad	1,800	12,600	7.00	3 W	€18+

Key takeaways:

• At the MCU level (Cortex-M vs RV32), performance per MHz is comparable — within 10–20%
• ARM application processors (Cortex-A) still lead in absolute raw performance
• RISC-V chips are consistently 30–60% cheaper at equivalent performance tiers
• RISC-V power efficiency is competitive, with some chips leading in performance-per-watt

Where ARM Wins on Performance

• High-performance application processors — Cortex-A78, A720, X4 are years ahead of RISC-V application cores
• GPU-integrated SoCs — ARM Mali and Immortalis GPUs have no RISC-V equivalent
• AI acceleration — ARM Ethos NPU is production-proven; RISC-V vector extension AI is emerging

Where RISC-V Wins on Performance

• Ultra-low-power MCUs — smaller cores, lower quiescent current
• Custom-accelerated workloads — custom ISA extensions can outperform ARM by 10–100× for specific algorithms
• FPGA soft cores — RISC-V cores synthesize efficiently on FPGAs; ARM has no equivalent FPGA licensing

Ecosystem Maturity: The Real Differentiator

Performance is close. The ecosystem gap is where the real differences live:

Development Tools

Tool Category	ARM	RISC-V
IDE	Keil MDK, IAR, STM32CubeIDE (mature, integrated)	PlatformIO, Freedom Studio, Eclipse-based (functional, less polished)
Compiler	ARM GCC, ARM Compiler 6, IAR (highly optimized)	GCC (good), LLVM/Clang (improving fast)
Debugger	J-Link, ST-Link, ULINK (hardware + software mature)	J-Link (partial), OpenOCD (good), custom probes
RTOS	FreeRTOS, Zephyr, Mbed OS, ThreadX (first-class support)	FreeRTOS, Zephyr, RT-Thread (good support, growing)
Linux	Mature, millions of deployments	Functional, mainline kernel support since 2022
Documentation	Extensive, professional-grade	Variable — excellent for major vendors, sparse for smaller ones

Software Library Availability

Library/Framework	ARM Support	RISC-V Support
TensorFlow Lite Micro	✅ Optimized (CMSIS-NN)	⚠️ Functional, not optimized
mbedTLS / WolfSSL	✅ Hardware-accelerated	⚠️ Software-only on most chips
CMSIS-DSP	✅ ARM-specific optimization	❌ No equivalent (use custom)
Bluetooth stack (NimBLE)	✅ Mature	✅ Good (ESP32-C3/C6)
Wi-Fi stack	✅ Mature	✅ Good (ESP32-C series)
USB stack (TinyUSB)	✅ Mature	✅ Growing
Motor control (FOC)	✅ ST, TI optimized libs	⚠️ Limited, mostly custom

Bottom line: ARM’s ecosystem is 15+ years more mature. If your project needs a specific peripheral library, RTOS integration, or optimized DSP routine, check RISC-V support before committing to it.

Licensing and Cost Analysis

ARM Licensing Structure

ARM licensing operates in tiers:

License Type	Cost	What You Get
Per-chip royalty	1–2% of chip price	Use pre-designed ARM core (e.g., Cortex-M4)
Architecture license	$1M–$10M+ upfront + royalties	Design your own ARM-compatible core
Flexible Access	$200K–$1M/year subscription	Access to full portfolio during development

RISC-V Cost Structure

Component	Cost
ISA license	$0 — open-source (BSD license)
Soft core IP	$0 (open-source: VexRiscv, PicoRV32, NEORV32) to $50K–$500K (commercial: SiFive, Andes)
Development tools	$0 (GCC, OpenOCD) to $5K–$20K (commercial IDEs)
RISC-V International membership	$0 (community) to $250K/year (strategic member)

Cost Impact at Scale

Production Volume	ARM Royalty Burden	RISC-V Savings
10,000 units	~€2,000–€20,000	Negligible benefit
100,000 units	~€20,000–€200,000	Meaningful savings
1,000,000 units	~€200,000–€2,000,000	Significant — can fund custom development
10,000,000 units	~€2M–€20M	Massive — this is why RISC-V adoption accelerates at scale

Key insight: For low-volume IoT products (<50K units), the cost difference is negligible — choose based on ecosystem. For high-volume consumer IoT (>500K units), RISC-V licensing savings become a strategic advantage.

RISC-V on FPGA: The Unique Advantage

One area where RISC-V has no ARM equivalent is FPGA deployment. ARM does not license its cores for FPGA synthesis (with rare exceptions). RISC-V soft cores are freely synthesizable:

Popular RISC-V FPGA Cores

Core	Language	Architecture	Size (LUTs)	MHz (Artix-7)	Features
PicoRV32	Verilog	RV32IMC	~1,500	250–400	Ultra-small, ideal for control
VexRiscv	SpinalHDL	RV32IMAFDC	1,500–4,000	200–300	Highly configurable, pipeline options
NEORV32	VHDL	RV32IMACB_Zicsr	3,000–5,000	100–200	Full SoC with peripherals, excellent docs
CVA6 (Ariane)	SystemVerilog	RV64IMAFDC	30,000+	100–150	Linux-capable, application-class
Ibex	SystemVerilog	RV32IMC	3,000–4,000	200+	lowRISC/Google, security-focused

Why this matters: You can put a RISC-V processor inside your FPGA alongside custom hardware accelerators — running firmware for configuration and control while the FPGA fabric handles real-time signal processing. This is the architecture behind modern Edge AI platforms and software-defined instruments.

At Inovasense, we regularly deploy RISC-V soft cores in our FPGA designs for control plane processing, protocol management, and configuration — eliminating the need for a separate MCU on the board.

EU Sovereignty and Strategic Considerations

The European Angle

The EU has made open architectures a strategic priority:

• European Processor Initiative (EPI) — building RISC-V-based HPC and automotive processors with €240M+ EU funding
• EU Chips Act — €43 billion investment explicitly supports open-source hardware and designs that reduce dependency on non-EU IP vendors
• DARE project — EU-funded RISC-V for space applications
• OpenHW Group (based in Europe) — collaborative RISC-V core development (CORE-V family)

For European hardware companies, RISC-V offers a path to architectural independence — no dependency on a single British/Japanese IP vendor (Arm Holdings, owned by SoftBank) for the core of your product.

Export Control Implications

Under EU dual-use regulations, the processor architecture itself generally isn’t controlled — but custom extensions for cryptography or signal processing may require export licensing. RISC-V’s transparency (open-source, auditable) can actually simplify security certification processes compared to ARM’s closed IP.

Supply Chain Diversification

ARM chips come from a limited set of vendors (ST, NXP, TI, Nordic, etc.). RISC-V silicon is available from a broader, more diverse supply chain:

• China — Espressif, Bouffalo Lab, WCH, Allwinner (cost-optimized IoT)
• Europe — Codasip, Andes (via TSMC EU), GreenWaves (AI-focused)
• US/Global — SiFive, Microchip (PolarFire SoC), Qualcomm (exploring RISC-V)

This diversity reduces single-vendor risk — a lesson many companies learned during the 2021–2023 chip shortage.

Decision Framework: When to Choose Which

Choose ARM When:

✅ Time-to-market is critical — ARM’s mature ecosystem means less debugging, more existing code, faster development ✅ You need proven, optimized libraries — DSP, ML inference, motor control with vendor-optimized code ✅ You’re building on an existing ARM codebase — porting from Cortex-M to Cortex-M is trivial; porting to RISC-V takes effort ✅ You need TrustZone security — ARM’s TrustZone is mature and certified (PSA Level 2+) ✅ High-performance application processor — Cortex-A series still leads RISC-V by 2–3 years ✅ Your team has ARM expertise — retraining costs are real

Choose RISC-V When:

✅ Cost per unit is critical — zero royalties compound at high volumes ✅ You need custom instructions — AI acceleration, custom crypto, domain-specific processing ✅ You’re deploying on FPGA — RISC-V soft cores are free, ARM is not available ✅ EU sovereignty matters — open-source ISA with no vendor dependency ✅ Ultra-low-power design — strip the ISA to bare minimum, eliminate unused logic ✅ You’re building a silicon product — SoC designers save millions in licensing ✅ Long product lifecycle (10+ years) — no risk of ISA vendor changing terms or increasing fees

The Hybrid Approach

Many sophisticated designs use both:

• RISC-V for the real-time control plane (small, deterministic, license-free)
• ARM for the application plane (Linux, GUI, networking, AI inference)
• FPGA for hardware acceleration (signal processing, custom interfaces)

This heterogeneous approach is increasingly common in industrial products and automotive systems.

Security Comparison

Security Feature	ARM	RISC-V
Trusted execution	TrustZone (mature, certified)	PMP + sPMP (functional, less mature)
Secure boot	Proven implementations	Available, vendor-dependent
Side-channel resistance	Extensive research, mitigations	Growing research, some gaps
Formal verification	Limited (closed source)	Possible (open source enables full audit)
Post-quantum readiness	Vendor-dependent	Custom extensions possible
CRA compliance	Straightforward with TrustZone	Achievable with careful design

Key insight for security-critical applications: ARM’s security story is more mature today. But RISC-V’s openness enables deeper security auditing — you can verify every transistor, which is impossible with ARM’s closed IP. For defense and critical infrastructure, this transparency is increasingly valued.

Getting Started with RISC-V

If you’re evaluating RISC-V for a new project:

Quick Start Hardware

Board	Chip	Price	Best For
ESP32-C3-DevKitM	ESP32-C3 (RV32IMC)	€8	Wi-Fi/BLE IoT, Arduino-compatible
Milk-V Duo	CV1800B (RV64GCV + ARM A53)	€9	Linux + RTOS, dual-architecture
Sipeed Longan Nano	GD32VF103 (RV32IMAC)	€5	Bare-metal embedded, STM32-like
SiFive HiFive Unmatched	SiFive U74 (RV64GC)	€600	Desktop Linux, SW development
Digilent Arty A7 + VexRiscv	FPGA soft core	€130	Custom RISC-V SoC prototyping

Learning Path

1. Start with ESP32-C3 — familiar Arduino/PlatformIO environment, Wi-Fi/BLE included
2. Try bare-metal — write startup code, understand CSRs, configure timer interrupts
3. Add an RTOS — port FreeRTOS or Zephyr to understand the HAL differences from ARM
4. Go FPGA — synthesize VexRiscv or NEORV32 on an Arty board and customize the SoC

Frequently Asked Questions

Will RISC-V replace ARM?

Not in the short term. ARM’s ecosystem advantage is too large to overcome quickly. However, RISC-V will capture significant market share in IoT microcontrollers, FPGA soft cores, custom AI accelerators, and high-volume consumer devices where licensing costs matter. By 2030, analysts project RISC-V will power 25–30% of IoT chips (up from ~10% in 2025). The two architectures will coexist, each dominating different segments.

Is RISC-V ready for production?

Yes. Over 10 billion RISC-V cores have shipped in production products. The ESP32-C3 alone has shipped in millions of Wi-Fi devices. SiFive’s cores are used in Western Digital hard drives (billions of units). China’s semiconductor industry has broadly adopted RISC-V for IoT and consumer electronics. For microcontroller-class applications, RISC-V is production-ready today.

Can I run Linux on RISC-V?

Yes. RISC-V has been supported in the mainline Linux kernel since version 4.15 (2018) with full support from 5.x onwards. 64-bit RISC-V (RV64GC) can run Ubuntu, Fedora, Debian, and Buildroot. Performance is adequate for embedded Linux applications (networking, UI, data processing) but not yet competitive with ARM Cortex-A for demanding workloads like Android or desktop computing.

How does RISC-V affect export controls?

The RISC-V ISA itself is not export-controlled — it’s an open standard. However, specific implementations (particular chip designs, custom extensions for cryptography) may fall under dual-use export regulations. The open-source nature of RISC-V can actually simplify export compliance because the architecture is publicly documented and auditable.

Can ARM code be ported to RISC-V?

Application-level code (C/C++) ports with minimal changes — recompile with a RISC-V GCC target. However, hardware-specific code requires rewriting: startup assembly, interrupt handlers, peripheral drivers, CMSIS/HAL calls, and any ARM-specific optimizations (NEON SIMD, TrustZone, DSP intrinsics). Budget 2–8 weeks for a typical MCU firmware port, depending on complexity and ARM-specific dependencies.

What is the RISC-V Vector Extension?

The RISC-V Vector Extension (RVV, ratified v1.0) is RISC-V’s answer to ARM’s Neon/SVE SIMD processing. It uses a scalable vector length model — the same binary runs efficiently on processors with different vector widths (128-bit to 1024-bit+). This makes it well-suited for AI inference, signal processing, and multimedia. RVV is becoming available in production silicon (e.g., SiFive P870, T-Head C908) and is a key differentiator for edge AI applications.

How Inovasense Can Help

We work with both ARM and RISC-V architectures across our hardware development projects:

• Architecture selection — data-driven recommendation based on your requirements, volume, and timeline
• RISC-V on FPGA — soft core integration in FPGA designs for control, protocol processing, and AI
• Custom SoC design — RISC-V-based system-on-chip architecture for custom silicon
• Firmware development — bare-metal and RTOS development for both ARM and RISC-V targets
• Edge AI acceleration — custom RISC-V extensions for neural network inference
• Security design — hardware root of trust implementation on both architectures
• EU compliance — CE marking and CRA readiness for RISC-V and ARM-based products

Contact us to discuss which architecture fits your next embedded project — or whether a hybrid approach gives you the best of both worlds.