Four days after the NU7 upgrade cut Zcash block times from 75 to 25 seconds, developers have posted a proposal to lower the block target spacing to 20 seconds. They want it in the next community poll and slated for NU7.1, a small follow-up upgrade.

The draft ZIP scales per-block shielded action limits by 4/5 (Orchard and Ironwood from 330 to 264 actions) and keeps the 2 MB block size limit. The per-block subsidy shrinks by the same factor and the halving interval moves from 5,040,000 to 6,300,000 blocks, so daily issuance stays unchanged.

In stress tests with 80 miners across 12 regions, full 2 MB blocks at 20 seconds produced orphan rates of 1.9% to 3.3%, below the 4.68% measured when 25-second blocks were deemed safe.

The authors frame it as a latency-only change for payments, exchange deposits and cross-chain swaps such as NEAR Intents. Some forum members argue that bigger speed gains would require a consensus change rather than shorter proof-of-work blocks.