Zcash GPU vs ASIC Mining: Why ASICs Won

The Short Answer

If someone asks you whether they should mine Zcash with a GPU in 2025, the answer is: no. Not marginally no - categorically no. The Antminer Z15 Pro achieves 840,000 Sol/s. A high-end RTX 4090 achieves approximately 1,200 Sol/s on Equihash. The ASIC is 700 times more powerful, and more importantly, it achieves 302 Sol/W vs a GPU's ~3–4 Sol/W - a 75–100× efficiency advantage. GPU Zcash mining at residential electricity rates results in a loss measured in dollars per day, not cents.

A Brief History: When GPUs Mined ZEC

Zcash launched in October 2016 with the Equihash proof-of-work algorithm specifically chosen because it was believed to be memory-hard and ASIC-resistant. For roughly 18 months, GPUs dominated ZEC mining. The Nvidia GTX 1070 and AMD RX 580 were popular choices, and GPU miners enjoyed a period of competitive ZEC mining.

That era ended in 2018 when Bitmain released the Antminer Z9 Mini - the first Zcash ASIC. The Z9 Mini delivered 10 KSol/s at 300W, dwarfing GPU performance. Within months, the Antminer Z9 (40.8 KSol/s) followed. GPU mining became economically unviable almost overnight as network difficulty spiked and GPU miners' share of block rewards collapsed.

The Efficiency Gap in 2025

*Daily ZEC at ~9 GH/s network hashrate, 3.125 ZEC block reward, 1% pool fee.

An RTX 4090 mining Zcash 24/7 earns approximately 0.000077 ZEC/day - worth roughly $0.006 at $80 ZEC. The electricity cost for 450W running 24h at $0.10/kWh is $1.08/day. That's a daily loss of over $1 per GPU, every day, indefinitely.

Why Equihash Didn't Stay ASIC-Resistant

Equihash was designed to require large amounts of memory, which was thought to prevent efficient ASIC implementation since memory is expensive to include on custom silicon. However, ASIC designers found ways to implement the algorithm efficiently despite the memory requirements. The memory-hardness that was supposed to level the playing field turned out to be an obstacle that purpose-built hardware could overcome with sufficient engineering investment.

This story has repeated itself across multiple "ASIC-resistant" algorithms - Ethash (Ethereum), CryptoNight, and Equihash all eventually saw ASICs appear. The lesson: no algorithm is permanently ASIC-resistant; it's only ASIC-resistant until someone invests enough to build the ASIC.

What This Means for Zcash Decentralisation

ASIC dominance concentrates mining power. When ASICs first appeared on ZEC, there was significant community debate about whether to fork to a new algorithm to restore GPU mining. The Zcash community ultimately chose not to fork, accepting that ASIC mining provides certain security benefits (higher capital cost to attack the network) even at the cost of mining centralisation. Today the ZEC network is overwhelmingly ASIC-mined, with GPU miners representing a negligible fraction of hashrate.

For independent miners, this means there is no shortcut: if you want to mine Zcash profitably, you need an ASIC. The Z15 Pro is the right hardware. See our full comparison for detailed rankings.