RISC-V and ARM are two different processor architectures, each with unique advantages and application scenarios. As technology evolves, both are becoming increasingly important in computing and embedded systems. This article compares the two to help users quickly understand their differences.
| Dimension | RISC-V | ARM |
|---|---|---|
| Architecture Type | Open instruction set (BSD/MIT license) | Proprietary instruction set (license fee) |
| Year Introduced | 2010 (UC Berkeley) | 1985 (ARM Ltd.) |
| Design Philosophy | Minimalist (base ISA ~40 instructions) | Incremental extensions (compatibility-first) |
| Typical Examples | Alibaba Xuantie C910, SiFive U74 | Apple M2 (ARMv8), Qualcomm Snapdragon 8 Gen2 (ARMv9) |
Key differences:
Instruction flexibility:
RISC-V allows custom user-defined instructions (e.g., AI acceleration).
ARM only allows predefined extensions (e.g., SVE2).
Bit-width support:
RISC-V supports 32/64/128-bit within the same ISA.
ARM requires switching between AArch32 and AArch64 states.
| Ecosystem Aspect | RISC-V Status | ARM Status |
|---|---|---|
| Development Tools | GCC/LLVM basic support | ARM Compiler, highly optimized |
| Operating Systems | Linux supported, Android in progress | Full support (Android/iOS/Windows) |
| Mass Production | Mainly low-to-mid range IoT chips | Full coverage: smartphones, servers, cars |
| Software Libraries | Gradually improving via community | Extensive commercial/open-source libraries |
Data points:
ARM-based chips annual shipments: ~30 billion (2023)
RISC-V-based chips annual shipments: ~2 billion (2023)
| Feature | RISC-V | ARM |
|---|---|---|
| Pipeline Design | Configurable (3–15 stages typical) | Fixed micro-architectures (Cortex-A/M/R) |
| Security | Dependent on extensions (P-ext/TEE) | Built-in TrustZone |
| Vector Computing | V extension (flexible widths) | SVE2 (fixed 128-bit) |
| Multi-core Coherency | Custom interconnect required | Standard AMBA bus |
Typical Configurations:
RISC-V: 12-stage out-of-order pipeline + custom AI instructions
ARM: Cortex-A78 with 10-stage pipeline + SVE2
| Domain | RISC-V Advantage Scenarios | ARM Advantage Scenarios |
|---|---|---|
| IoT Devices | Ultra-low power MCUs (e.g., GD32V series) | High-performance MCUs (Cortex-M7) |
| Edge Compute | Customized AI accelerators (Canaan K230) | General-purpose compute (Rockchip RK3588) |
| Servers | Energy efficiency (StarFive STAR-5) | Performance priority (Ampere Altra) |
| Automotive | Coprocessors in domain controllers | Main SoCs (Qualcomm SA8295) |
| Aspect | RISC-V | ARM |
|---|---|---|
| Licensing | Royalty-free (optional paid IP) | License fee + per-chip royalty |
| IP Vendors | SiFive, Andes, T-Head | ARM itself |
| Customization Cost | Lower (open-source toolchains) | Higher (expensive architecture license) |
Cost Example:
RISC-V: Alibaba Xuantie E902 core (free)
ARM: Cortex-A55 license fee (~$0.1–0.5 per core per chip)
RISC-V:
Android basic support in 2023
Expected entry into mainstream data centers by 2025
Highlighted in China’s “14th Five-Year Plan”
ARM:
Transition to ARMv9 (all 2023 smartphone SoCs)
Server market share exceeds 10% (driven by AWS Graviton)
Choose RISC-V when:
✓ Full autonomy and control are required
✓ Strong customization needs
✓ Extreme cost sensitivity
Choose ARM when:
✓ Mature ecosystem is a priority
✓ Maximum performance is needed
✓ Time-to-market is critical
Note: The two are not complete substitutes. A future trend may be hybrid architectures with ARM as the main processor and RISC-V as a coprocessor.
