Solana Speeds Up Blocks 17% as Transaction Capacity Holds Steady
A slot is the brief window in which a designated Solana validator can add a block, making its duration a key measure of how quickly wallets, exchanges, oracles and automated market makers receive fresh on-chain information. The change is part of SIMD-0525, a staged plan to cut slot times from 400 milliseconds toward 200 milliseconds. Its main goal is lower latency and a shorter period in which any one validator controls transaction ordering, rather than a direct increase in network throughput.
Solana mainnet-beta activated 250-millisecond slots at epoch 1037 at 05:06 UTC on Sept. 18, 2026, down from 300 milliseconds. The shift raises the target rate to four slots a second from about 3.3, a nearly 17% acceleration, and cuts a four-slot validator leader window to one second from 1.2 seconds. Under SIMD-0525, however, the computation and data allowed per slot fall proportionately, leaving total transaction capacity broadly unchanged. Expected epoch duration drops to about 30 hours from 36, while the proposed 200-millisecond stage has no mainnet date.
All Coverage
3 original reportsThe Backstory
The history behind this eventSolana Triples Transaction Limit With Mainnet Upgrade
Solana is a high-speed blockchain competing with Ethereum for developers and activity in smart contracts and decentralized applications. Transaction-size limits determine how many instructions, signatures and proofs can be packaged into a single operation. Expanding that envelope gives developers more flexibility to build complex products without splitting workflows across several transactions, narrowing a technical gap between Solana and its larger rival.
Solana activated its Transaction V1 format on mainnet, according to reports published Sept. 15, 2026, raising the maximum transaction size to 4,096 bytes from 1,232 bytes. The new ceiling is about 3.3 times the previous limit and adds 2,864 bytes of capacity. That room can accommodate multi-step trades, corporate-wallet approval flows and privacy proofs, allowing more data and instructions to be processed within a single transaction.
Solana Cuts Mainnet Slot Time to 350 Milliseconds
Solana coordinates validators and transaction processing around a fixed slot schedule, making slot duration a key measure of network responsiveness. Shorter slots can reduce confirmation latency for decentralized finance, onchain trading and payments, where fractions of a second may affect execution. The change is also a test of whether validators, infrastructure providers and applications can keep pace without sacrificing network stability.
The Solana mainnet has begun its first-ever slot-time reduction, cutting the interval to 350 milliseconds from about 400 milliseconds starting with Epoch 1020. The 12.5% reduction marks an initial step toward a longer-term target of 200 milliseconds. Core developers advised teams to update relevant SDK constants and account for the delayed-activation mechanism so applications do not rely on outdated timing assumptions.
Subscribe to Mark Radar Weekly
Every Friday, the week's strongest signals in your inbox. Unsubscribe anytime.
If you search news on Google, you can set Mark Radar as a preferred source—our coverage will show up more often in your results. Set as preferred source on Google →