The Thanos network upgrade has activated on Ethereum Classic mainnet at block 11,700,000, implementing ECIP-1099 to modify the ETChash DAG size calculation.
The DAG Size Issue
The Ethash/ETChash algorithm requires miners to store a DAG (Directed Acyclic Graph) in GPU memory. This DAG grows over time, eventually exceeding the memory of 4GB GPUs.
ECIP-1099 Solution
The Thanos upgrade implements ECIP-1099, which:
- Resets the DAG epoch to allow 4GB GPUs to continue mining
- Modifies the DAG growth schedule
- Maintains security while extending hardware compatibility
Impact
This change:
- Extends the useful life of 4GB GPU mining hardware
- Keeps mining accessible to more participants
- Maintains network hashrate from smaller miners
Algorithm Note
With this change, ETC's mining algorithm is now called "ETChash" to distinguish it from Ethereum's Ethash, though they remain similar in fundamental operation.
The upgrade demonstrates ETC's commitment to maintaining accessible mining while balancing security considerations.