Zcash mining firmware, by GHOST Inc.

Zcash launched on October 28, 2016, with a proof-of-work algorithm called Equihash (200,9). Early miners ran software on CPUs and GPUs. Today, specialized Equihash ASICs dominate. Through every hardware generation, a miner's economics have depended on the same moving parts: solutions per second, watts at the wall, network difficulty, block subsidy, pool performance, uptime, and the market price of ZEC.

• Zcash launch
• Protocol specification

1. 2016–17

   The CPU and GPU era

   At launch, miners competed with general-purpose hardware and rapidly improving mining software. An open-source miner challenge recognized both CPU and GPU implementations. Zcash also introduced a mining slow start: the block subsidy ramped up over the first 5,000 blocks rather than arriving at its full amount on day one. Early ZEC market quotes were exceptionally volatile in a thin market, so launch-day prices make a poor benchmark for a real mining business. During the initial reward era, miners received 80% of the block subsidy; the other 20% was the Founders' Reward.

   Why it mattered to minersSoftware optimization, GPU availability, and access to pools mattered more than buying a purpose-built machine. Rising coin prices attracted more hashpower, while difficulty adjusted the share of rewards available to each rig.

   Sources

   • Miner challenge
   • Slow start
   • Original reward split

   

   SOFTWARE

   CPU minerOpen-source miners

   

   SOFTWARE

   GPU rigEquihash solvers

   • Slow startThe block subsidy ramped up over the first 5,000 blocks.
   • 80 / 20Miners received 80% of the subsidy; 20% went to the Founders' Reward.
2. 2018

   Equihash ASICs change the field

   Bitmain's Antminer Z9 mini and Z9 marked the decisive move toward dedicated Equihash hardware. Bitmain lists the Z9 mini at 10 KSol/s, 300 W and the Z9 at 40.8–42.0 KSol/s, 1,150 W, at their published operating points. Innosilicon also shipped its A9 ZMaster, specified at 50 KSol/s and 620 W. Its June 2018 announcement shows that this was a contest between hardware makers, not simply one Bitmain release. The introduction of ASICs triggered a serious debate over whether Zcash should change its proof of work to protect GPU mining; the network ultimately continued using Equihash (200,9). The Zcash Foundation's mid-2018 study cautioned that hidden ASIC activity could not be measured precisely.

   Network changes: Overwinter made future consensus upgrades safer. Sapling activated October 28, bringing a major improvement in shielded-transaction performance. Neither event made the new Equihash ASICs obsolete.

   Sources

   • Z9 mini
   • Z9
   • Innosilicon announcement
   • A9 manual
   • Foundation study
   • ASIC debate
   • Overwinter
   • Sapling activation

   

   BITMAINGHOST SHELL

   Z9 mini10 KSol/s · 300 W

   30.0 J/KSol

   

   INNOSILICON

   A9 ZMaster50 KSol/s · 620 W

   12.4 J/KSol

   

   BITMAINGHOST SHELL

   Z940.8 KSol/s · 1,150 W

   28.2 J/KSol

   • OverwinterMade future consensus upgrades safer.
   • Sapling · Oct 28Major shielded-transaction performance gains. ASICs unaffected.
3. 2019

   The Z11 generation, a security disclosure, and faster blocks

   The Antminer Z11 raised Bitmain's published performance to 135 KSol/s at 1,418 W, about 10.5 J/KSol. Compared with the Z9's stated figures, it offered substantially more work per watt.

   Innosilicon's A9+ ZMaster and A9++ ZMaster also belong in this generation. The A9+ was rated 120 KSol/s at 1,550 W; the A9++ increased to 140 KSol/s at about the same wall power. A mining pool's contemporary equipment guide documents both operating models, while an archived A9++ product sheet states the latter rating. These machines competed with the Z11 but differ in controls, service parts, and firmware.

   In February, Zcash publicly disclosed a critical Sprout counterfeiting vulnerability discovered in March 2018. It had been fixed by the October 2018 Sapling activation. The Electric Coin Company reported no evidence that counterfeit ZEC had been created. This was a cryptographic supply risk, not an exploit in an ASIC.

   In December, Blossom reduced the target interval from 150 to 75 seconds and reduced the subsidy per block accordingly. That meant more frequent blocks, not a doubling of new ZEC per unit of time. Mining software, pool infrastructure, and economic calculators had to account for the new cadence.

   Sources

   • Z11 specifications
   • 2Miners' equipment guide
   • A9++ product sheet
   • Vulnerability disclosure
   • Blossom mechanics
   • Blossom upgrade

   

   INNOSILICON

   A9+ ZMaster120 KSol/s · 1,550 W

   12.9 J/KSol

   

   BITMAINGHOST SHELL

   Z11135 KSol/s · 1,418 W

   10.5 J/KSol

   

   INNOSILICON

   A9++ ZMaster140 KSol/s · 1,550 W

   11.1 J/KSol

   • DisclosureSprout counterfeiting flaw revealed — fixed by Sapling, no evidence of exploitation.
   • BlossomBlock time 150 → 75 s. Per-block subsidy halved with it, so issuance over time held steady.
4. 2020–21

   The Z15 family and the first halving

   Bitmain's Z15 represented another large efficiency jump: 420 KSol/s at 1,510 W, or 3.6 J/KSol. The related Z15j was specified at 320 KSol/s at 1,510 W; the Z15e at 200 KSol/s at 1,510 W. These are distinct model ratings, not interchangeable performance claims. Real wall power and hash rate vary with unit condition, supply, ambient temperature, and tuning.

   Heartwood in July 2020 allowed miners and pools to direct coinbase rewards to Sapling shielded addresses. On November 18, 2020, the first Zcash halving coincided with Canopy: the total block subsidy fell by half, and a new development-fund structure replaced the expiring Founders' Reward. Miners continued to receive 80% of the block subsidy. Bitmain's hardware kept doing Equihash work; pool and node operators needed to follow the new consensus rules.

   Why it mattered to minersThe Z15 could improve efficiency per solution, but a halving reduces ZEC earned per unit of network hashpower if difficulty, fees, and all other factors are unchanged. Hardware efficiency and power price became still more consequential.

   Sources

   • Bitmain Z15 family specifications
   • Heartwood release
   • Canopy

   

   BITMAINGHOST SHELL

   Z15420 KSol/s · 1,510 W

   3.6 J/KSol

   

   BITMAINGHOST SHELL

   Z15j320 KSol/s · 1,510 W

   4.7 J/KSol

   SHARED Z15 CHASSIS

   

   BITMAINGHOST SHELL

   Z15e200 KSol/s · 1,510 W

   7.6 J/KSol

   SHARED Z15 CHASSIS

   • HeartwoodCoinbase rewards can pay to Sapling shielded addresses.
   • Canopy · Nov 18First halving. A dev fund replaced the Founders' Reward; miners kept 80%.
5. 2022–23

   NU5, node load, and the Z15 Pro

   Network Upgrade 5 (NU5) activated May 31, 2022. It introduced the Orchard shielded pool and Halo proving system. Mining pools and node operators had to update their software and check block-template compatibility; ASICs continued solving the Equihash work they were assigned. Beginning in June 2022, a large rise in shielded-transaction activity created severe wallet-sync and node-performance problems, prompting a long series of software improvements.

   In March 2023, releases zcashd 5.3.3 and 5.4.2 fixed memory-exhaustion vulnerabilities that could be used to crash nodes. ECC reported no evidence of exploitation. A miner's ASIC was not the vulnerable component, but a pool or solo miner relying on an affected node could have been disrupted.

   Bitmain documented the Z15 Pro in 2023 at 840 KSol/s and 2,780 W, or 3.31 J/KSol at the stated test conditions. That is twice the Z15's nameplate hashrate, with a smaller gain in efficiency per solution. It also brought a much larger wall-power requirement, making PSU, circuits, heat removal, and actual measured performance important in deployment decisions.

   Sources

   • NU5 release
   • Network load
   • Security release
   • Z15 Pro specifications

   

   BITMAINGHOST SHELL

   Z15 Pro840 KSol/s · 2,780 W

   3.31 J/KSol

   • NU5 · May 31Orchard pool and Halo proofs. Pools had to update block templates.
   • 2022 loadA surge in shielded activity strained wallets and nodes.
   • Mar 2023zcashd 5.3.3 / 5.4.2 fixed node-crashing memory exhaustion.
6. 2024–25

   Second halving, funding changes, and a price surge

   The second halving and NU6 arrived on November 23, 2024. The total subsidy dropped from 3.125 to 1.5625 ZEC per block. NU6 also changed how the development share was held and distributed. As with the first halving, the direct effect on a miner is fewer new coins per unit of network work, all else equal.

   NU6.1 in 2025 updated the funding mechanism, giving community and coinholder processes a role in grant decisions. It was a pool/node compatibility and reward-allocation milestone, not a replacement of Equihash hardware. The same year brought one of ZEC's most consequential price moves since 2018: Coinbase reported a rise from about $74 in late September to above $734 in early November 2025. A higher ZEC price can improve dollar revenue for miners, but the network may respond over time as more hashpower comes online.

   Sources

   • ECC halving and NU6 explanation
   • NU6.1 deployment
   • Coinbase market recap

   • NU6 · Nov 23Second halving: 3.125 → 1.5625 ZEC per block.
   • NU6.1Community and coinholder roles in grant decisions.
   • Sep–Nov 2025ZEC rose from about $74 to above $734.
7. 2026

   Emergency fixes, Ironwood, and the node transition

   A critical vulnerability in the Orchard proof circuit led to emergency network action. NU6.2 activated June 3, 2026, permanently patching the vulnerability and restoring full shielded functionality. Ironwood (NU6.3) activated July 28, 2026, introducing a new shielded pool designed to make circulating-supply integrity independently verifiable. These were serious protocol events; they did not change Zcash's Equihash mining algorithm.

   Just before Ironwood, zcashd reached end of life and did not support NU6.3. Mining pools and solo-mining infrastructure had to migrate to Zebra for compatible node and block-template service. A July 2026 Zebra release also repaired a getblocktemplate edge case that could have supplied an oversized, invalid candidate block and wasted a miner's work under specific conditions. The Foundation did not report a consensus split from that issue.

   Several reseller catalogs began listing a “Z15K” at 525 KSol/s and 2,483 W in 2026. We have not found a matching Bitmain specification or manufacturer release announcement. The diagram marks this listing separately; those numbers should not be treated as independently verified hardware specifications. Likewise, historical catalog listings for the ASICminer Zeon should not be conflated with established, independently documented deployments.

   Sources

   • NU6.2
   • Ironwood
   • zcashd deprecation
   • Zebra 6.1.0 security fixes
   • Example Z15K catalog listing
   • 2018 community discussion of Zeon claims

   

   UNVERIFIEDGHOST SHELL

   Z15K*525 KSol/s · 2,483 W

   ~4.7 J/KSol

   RESELLER LISTING

   • NU6.2 · Jun 3Patched a critical Orchard proof-circuit vulnerability.
   • NU6.3 · Jul 28Ironwood: a new shielded pool with verifiable supply.
   • zcashd EOLZebra now supplies mining nodes and getblocktemplate.