Algorithms

Etchash

Ethereum Classic's memory-hard algorithm — a recalibrated Ethash that keeps 3–4 GB GPUs viable and broke legacy ASIC compatibility.

Adopted in November 2020 (ECIP-1099), Etchash halved the DAG epoch size of Ethash so older GPUs could keep mining ETC, while invalidating existing Ethash ASICs. Mining performance is bound by memory bandwidth: the miner constantly reads pseudo-random slices of the multi-gigabyte DAG held in VRAM.

Since Ethereum's 2022 move to proof-of-stake, Etchash is the largest GPU-minable algorithm by market cap. Tuning is mandatory — undervolted cards deliver 20–40% better efficiency than stock settings.

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→ Etchash algorithm page
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Related Terms

DAG (Directed Acyclic Graph)
GPU Mining

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