In Part 1, we laid out the architectural reasons ZKM selected MIPS32r2 as the foundation for our zkVM: higher opcode density, stable specification, and hardware-proven toolchain maturity. In this follow-up, we go a level deeper - exploring how microarchitectural traits of MIPS align with zero-knowledge circuit design, and where RISC-V introduces complexity that must be actively mitigated.
In traditional computing, instruction decoding is handled by hardware logic with virtually no performance penalty. In a zkVM, however, instruction decode logic must be expressed as arithmetic constraints. Every bit that must be matched, selected, or transformed adds rows to the trace and selectors to the constraint system. Complexity here directly impacts prover performance.
MIPS32r2 was designed around simplicity, uniformity, and fixed formats. These traits directly reduce the arithmetic burden in zkVM contexts:
These traits enable deterministic, low-overhead instruction decoding in ZK. They also reduce the need for intermediate representations (IR) or lookup-based opcode dispatch systems, which are often used in other zkVMs to compensate for less structured ISAs.
RISC-V’s instruction set was designed for hardware modularity and long-term extensibility. While this makes sense for silicon-level design, it creates overhead in a proving context:
These challenges are surmountable, and several zkVM teams are actively working around them. But the cost is real: more constraints, more trace length, and often, slower proving performance.
The guiding principle here is that zero-knowledge circuits reward determinism and punish variability. The more structured and predictable the instruction set, the fewer gates are needed to enforce correctness. MIPS delivers that structure natively, without sacrificing expressiveness.
For a MIPS-based zkVM, this translates to:
These aren’t theoretical advantages. They impact prover throughput, memory footprint, and composability when integrated into recursive systems.
ZKM’s approach isn’t limited to ISA choice. We build the entire stack - from compiler to constraint system to recursive verifier. That gives us freedom to tune each layer without being constrained by external toolchains or protocol mismatches.
When building verifiable compute systems, architectural simplicity compounds. It makes proof generation faster, circuit auditing easier, and version upgrades safer. MIPS gives us that simplicity not just at the opcode level, but at the circuit boundary.
This is why our production-ready zkVM is built on MIPS. Not just because it performs better - but because it verifies better.
Subscribe to the ZKM Blog to stay updated with the latest research by ZKM.
Get started with ZKM: Docs
Build with ZKM: Gitub
In Part 1, we laid out the architectural reasons ZKM selected MIPS32r2 as the foundation for our zkVM: higher opcode density, stable specification, and hardware-proven toolchain maturity. In this follow-up, we go a level deeper - exploring how microarchitectural traits of MIPS align with zero-knowledge circuit design, and where RISC-V introduces complexity that must be actively mitigated.
In traditional computing, instruction decoding is handled by hardware logic with virtually no performance penalty. In a zkVM, however, instruction decode logic must be expressed as arithmetic constraints. Every bit that must be matched, selected, or transformed adds rows to the trace and selectors to the constraint system. Complexity here directly impacts prover performance.
MIPS32r2 was designed around simplicity, uniformity, and fixed formats. These traits directly reduce the arithmetic burden in zkVM contexts:
These traits enable deterministic, low-overhead instruction decoding in ZK. They also reduce the need for intermediate representations (IR) or lookup-based opcode dispatch systems, which are often used in other zkVMs to compensate for less structured ISAs.
RISC-V’s instruction set was designed for hardware modularity and long-term extensibility. While this makes sense for silicon-level design, it creates overhead in a proving context:
These challenges are surmountable, and several zkVM teams are actively working around them. But the cost is real: more constraints, more trace length, and often, slower proving performance.
The guiding principle here is that zero-knowledge circuits reward determinism and punish variability. The more structured and predictable the instruction set, the fewer gates are needed to enforce correctness. MIPS delivers that structure natively, without sacrificing expressiveness.
For a MIPS-based zkVM, this translates to:
These aren’t theoretical advantages. They impact prover throughput, memory footprint, and composability when integrated into recursive systems.
ZKM’s approach isn’t limited to ISA choice. We build the entire stack - from compiler to constraint system to recursive verifier. That gives us freedom to tune each layer without being constrained by external toolchains or protocol mismatches.
When building verifiable compute systems, architectural simplicity compounds. It makes proof generation faster, circuit auditing easier, and version upgrades safer. MIPS gives us that simplicity not just at the opcode level, but at the circuit boundary.
This is why our production-ready zkVM is built on MIPS. Not just because it performs better - but because it verifies better.
Subscribe to the ZKM Blog to stay updated with the latest research by ZKM.
Get started with ZKM: Docs
Build with ZKM: Gitub
