Solana Speeds Up Block Times, Aiming to Cut Them in Half

TL;DR

• Solana reduced its target slot time from 400 milliseconds to 350 milliseconds following a successful mainnet upgrade.

• The change is the first phase of a broader proposal to lower slot times to 200 milliseconds through additional 50-millisecond reductions.

• Shorter slots reduce transaction confirmation latency and decrease epoch duration from approximately 48 hours to 42 hours.

Solana Mainnet Upgrade Reduces Slot Times to 350 Milliseconds

Solana has completed a mainnet upgrade that reduces its target slot time from 400 milliseconds to 350 milliseconds, marking an important step toward faster transaction confirmations.

A slot represents the brief period during which a designated validator can produce a block of transactions on the Solana blockchain.

The upgrade, activated Friday morning, shortens that window by 50 milliseconds, reducing the target slot duration by 12.5%.

The adjustment is the first implementation stage under SIMD-0525, a Solana improvement proposal outlining plans to eventually reduce target slot times to 200 milliseconds.

The proposal, merged on May 14, would ultimately halve Solana’s longstanding 400-millisecond target.

Faster Slots Improve Transaction Confirmation Times

The primary objective of the upgrade is to reduce the time users wait for transactions to progress through the network.

According to the proposal, shorter slots lower confirmation and finalization latency because consensus thresholds measured by slot count can be reached more quickly in real-world time.

The faster schedule also reduces the time a single validator controls block production.

Solana validators typically remain responsible for four consecutive slots. Under the previous 400-millisecond target, validators held that role for approximately 1.6 seconds.

With the new 350-millisecond target, leadership rotates approximately every 1.4 seconds.

The proposal’s authors argue that shorter validator windows also limit the time available for an individual validator to delay or rearrange transactions before another validator takes over.

The upgrade also shortens Solana’s epochs, which each contain 432,000 slots. At the previous target of 400 milliseconds per slot, an epoch took approximately 48 hours to complete.

With the new 350-millisecond target, the expected duration falls to approximately 42 hours.

A comparison of network performance before and after the upgrade showed a similar improvement.

A 1,000-slot period shortly before the change took 415 seconds, while a comparable 1,000-slot period later in epoch 1020 took 368 seconds.

Although actual slot times can vary, the measurements suggest the network is operating closer to its newly reduced timing target.

Solana Plans Additional Reductions Toward 200 Milliseconds

Solana developers intend to lower slot times through three additional 50-millisecond reductions.

The planned sequence would bring the target from 350 milliseconds to 300 milliseconds, followed by 250 milliseconds and ultimately 200 milliseconds.

According to the Solana Foundation’s upgrade overview, each stage will be activated separately.

Developers can pause the rollout if too many validators fail to produce blocks during their assigned slots.

The next planned target is 300 milliseconds, although no activation date has been announced.

Before proceeding, developers intend to monitor network performance under the current 350-millisecond schedule.

Despite reducing transaction latency, the upgrade does not necessarily allow Solana to process more total work per second.

Validators produce blocks more frequently under shorter slot times, but each slot carries less work.

Consequently, the change primarily improves responsiveness and validator rotation rather than automatically expanding overall transaction-processing capacity.

Network throughput depends on other factors, including compute limits, validator performance, and the amount of work permitted within individual blocks.

Solana has pursued separate upgrades to increase those limits.

In July 2025, developers implemented a higher block compute limit of 100 million compute units, expanding the amount of transaction-processing work permitted within each block.

Network Activity Continues to Increase

The upgrade comes as Solana has experienced a notable increase in non-vote transactions since the beginning of the year.

Non-vote transactions include user and application activity rather than validator voting operations required to maintain network consensus.

Growth in this category suggests rising usage across applications and services built on the Solana blockchain.

Faster slot times could improve the user experience as network activity increases, particularly for applications that benefit from quicker transaction confirmation.

Solana has also improved its validator ecosystem through the introduction of additional client software.

Jump Crypto’s Firedancer client launched on mainnet in December. Firedancer is written in the C programming language, distinguishing it from the Rust-based Agave client and its widely used Jito-Agave fork.

The addition of an independently developed validator client strengthens network diversity and can improve resilience by reducing dependence on a single software implementation.

Alpenglow Upgrade Targets Faster Finality

Although Solana’s slot times are decreasing, full transaction finality still takes significantly longer.

Finality refers to the point at which the network considers a block effectively irreversible.

Solana’s current finality time is approximately 12.8 seconds.

The proposed Alpenglow upgrade, which remains under development, aims to reduce that figure to approximately 150 milliseconds.

If implemented successfully, Alpenglow would complement shorter slot times by dramatically reducing the time required for transactions to become final.

For now, Solana developers are focused on evaluating the network’s performance at 350 milliseconds before determining when to introduce the next reduction.