Following the implementation of Ethereum's Dencun upgrade on March 13, Layer 2 networks supporting EIP-4844 have experienced significant reductions in transaction fees, ranging from 50% to 98%.

Data from Dune Analytics reveals a substantial decline in average transaction fees on prominent Layer 2 networks like Arbitrum, Optimism, Base, and ZkSync Era, with decreases of 87%, 69%, 88%, and 63% respectively within the past 48 hours. Additionally, the median price of swaps on Uniswap has plummeted by 96%, dropping from $1.19 to a mere $0.05 post the activation of Dencun.

Notably, Uniswap's creator, Hayden Adams, shared a screenshot indicating that gas fees on Uniswap v3's Optimism deployment had decreased to less than $0.01, showcasing the tangible impact of the EIP-4844 upgrade, also known as proto-danksharding.

EIP-4844's key modification involved replacing the gas-intensive calldata with binary large objects (blob) on Layer 2 networks. This change has significantly reduced transaction costs, with calldata previously accounting for a substantial portion (between 73% and 90%) of Layer 2 transaction expenses before the Dencun upgrade.

Further data from GrowThePie illustrates substantial average daily fee reductions of 96% on Base, 97% on OP Mainnet, and 98% on Starknet since the activation of Dencun. While ZkSync witnessed a 49% fee decrease and Arbitrum experienced a 50% reduction, Arbitrum's full integration of EIP-4844 is scheduled for March 19, promising additional gas-saving measures.

The variations in fee reductions among networks like ZkSync Era, OP Mainnet, and Base can be attributed to their distinct architectural approaches, with ZK-rollup networks like ZkSync offering unique performance advantages. Starknet, another ZK-rollup network, plans to introduce further fee-saving initiatives alongside the Dencun upgrade, aiming to double the cost reductions achieved by EIP-4844 and eventually subsidize fees to their anticipated levels upon completion of the rollout.