Buterin Says Ethereum’s Biggest Bottlenecks Are State Tree and VM, Proposes Deep Fix

Buterin proposes binary state trees and eventual RISC-V VM shift to improve Ethereum’s proving efficiency and execution simplicity.

Vitalik Buterin has proposed execution-layer changes that could fundamentally reshape Ethereum’s core architecture. The project’s co-founder argued that deep modifications to the network’s state tree and virtual machine are necessary to remove what he described as the chain’s biggest proving bottlenecks.

In a detailed post on X, Buterin said that the state tree and VM together account for more than 80% of the constraints that affect proof efficiency and called them “basically mandatory” targets if Ethereum wants to enable scalable client-side and zero-knowledge proving use cases.

Ethereum Overhaul

He pointed to EIP-7864, a proposal developed by Guillaume Ballet and others, which would replace Ethereum’s current hexary Keccak-based Merkle Patricia Tree with a binary tree built on a more efficient hash function. According to Buterin, the change would shorten Merkle branches by roughly four times, by cutting bandwidth requirements and making client-side branch verification significantly cheaper.

This could reduce data costs for tools such as Helios and private information retrieval systems by 4x, Buterin added. Proving efficiency could also be improved by 3-4 times from shorter branches alone. He expects additional gains if Ethereum shifts to hash functions such as BLAKE3, which is estimated to be three times more efficient than Keccak. Meanwhile, a Poseidon variant could offer up to 100 times improvement, though he noted further security work would be required.

The proposed binary design would also group storage slots into 64-256-slot “pages” and allow more efficient loading and editing of adjacent storage, potentially saving more than 10,000 gas per transaction for applications that access early storage slots. Buterin explained that a prover-friendly state tree would also allow zero-knowledge applications to compose directly with Ethereum’s state instead of building independent trees, while at the same time simplifying the structure and enabling metadata additions for future state expiry mechanisms.

Beyond the state tree overhaul, Buterin made the case for eventually replacing the Ethereum Virtual Machine with a RISC-V-based VM, as he described the idea as longer-term and non-consensus. But he expressed high conviction that it would become “the obvious thing to do” after state roadmap upgrades are complete.

Possible Deployment Roadmap

The Ethereum co-founder said that a RISC-V VM would be more execution-efficient, more prover-friendly, and simpler, while noting that many existing provers are already written in RISC-V and that an interpreter could be implemented in only a few hundred lines of code. He detailed a phased transition plan beginning with using the new VM for precompiles, then allowing developers to deploy contracts directly in the new VM, and ultimately retiring the EVM into a compatibility layer written as a smart contract in the new system.

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Under that roadmap, users would retain full backward compatibility apart from gas cost changes, which Buterin said would likely be overshadowed by scaling improvements in the coming years.

Buterin’s latest push comes just days after he introduced a quantum-resistance roadmap, which included proposals to replace consensus-layer BLS signatures with hash-based schemes such as Winternitz variants.