Zcash Developer Proposes 8 MB Blocks in NU8 as Shielded Usage Grows

Zcash developers are pushing two capacity changes in the same week: a faster block interval and a block size four times larger. Shielded activity is climbing, yet it remains a sliver of what the chain can already carry.

• 8 MB blocks: ValarDragon asked on the community forum for NU8, aimed at late January 2027, to lift the cap from 2 MB to 8 MB, and said the final size could be higher.
• The 200 TPS pitch: He projected 200 shielded transactions per second once the Tachyon pool and bigger blocks work together.
• The rest of NU8: An extensible transaction format for hardware wallets, post-quantum transparent opcodes, a deadline after which Sapling stops accepting deposits, and an end to consensus branch ID changes that break wallets.
• 20-second blocks: Two days after NU7 cut the interval to 25 seconds from 75, developers proposed trimming it to 20, headed for a community vote and NU7.1. Reports say daily private-transaction throughput and the issuance schedule would not change.
• Interim step: An open draft would raise the limit to 3 MB, and ValarDragon called 3 MB and 4 MB safe at 20-second blocks.

• Usage is rising: Shielded transactions made up 52.7% of non-coinbase activity in the third quarter, up from 27.4%, per Blockworks.
• Holdings are growing: About 4.9 million ZEC, roughly 29% of supply, sits in shielded pools.
• Volume is small: Roughly 710,000 transactions in the quarter, an average near 0.09 per second.
• Room to spare: Earlier design work put Orchard’s ceiling at 2.9 transactions per second at 75-second blocks, and 8.7 at 25 seconds.

Nothing in the proposals shows blocks running full, and no fee data was published. 

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• Wallets first: Str4d of ZODL said the rationale looks only at full nodes. With no specification yet for private syncing, most wallets will lack fixes within two months, so any increase should be tested against the light client protocol.
• Storage: At 25-second spacing, full 8 MB blocks would add about 28 GB of chain data a day, though real blocks are far smaller.
• Schedule: Str4d called the January target tight, noting Tachyon’s specification drafts were still in a fork.

The proposed changes could expand Zcash’s capacity as shielded activity grows, but current transaction volumes remain well below the network’s existing limits. Wallet compatibility, storage requirements, and the tight development timeline will be key factors in determining whether the upgrades can be implemented safely.