The Firedancer team at Jump Crypto has proposed a significant change to the Solana network: removing the fixed block compute unit (CU) limit to enhance network performance and incentivize validators to upgrade their hardware. The proposal, named SIMD-0370, suggests allowing block sizes to adjust based on the transaction capacity of high-performance validators after the Alpenglow upgrade.
Currently, Solana has a block limit of 60 million CUs, which is expected to increase to 100 million with SIMD-0286. Firedancer argues that this static limit is unnecessary after the Alpenglow upgrade, as blocks that cannot be processed in time can be automatically skipped. Alpenglow is a forthcoming network upgrade that aims to reduce block finality from 12.8 seconds to as little as 100–150 milliseconds, unlocking greater efficiency by reducing congestion and eliminating redundant gossip messaging.
The core idea behind SIMD-0370 is that validator performance should determine network capacity rather than an arbitrary ceiling. By removing static block caps, slower validators would skip more complex blocks, leaving them for better-equipped validators to handle. This creates a "performance flywheel," where block producers can pack more transactions to earn more fees. Validators that skip blocks would lose rewards, incentivizing them to upgrade hardware and optimize code. This, in turn, would lead to better performance across the network, allowing producers to safely push limits further.
The Firedancer team believes this change will allow network capacity to grow based on market dynamics rather than fixed limits. Increasing block sizes over time could mean more transaction capacity and lower congestion for users and application developers.
However, the proposal also raises concerns about potential centralization and stability risks. Roger Wattenhofer, head of research at Anza, warned that removing the block limit could introduce technical risks and foster centralization. Experts also argue that the impact of larger blocks on the network's distribution time and the potential impact on concurrent block producer designs should be carefully considered.
Despite these concerns, proponents argue that the benefits of removing the block limit outweigh the risks. They believe that the change will create a more dynamic and efficient network that can better meet the demands of its users.
SIMD-0370 is currently in the "review" phase. If adopted, it could significantly increase Solana's network throughput and impact the dynamics of validators, making it more competitive against other high-throughput blockchains.
