ASICs, or application-specific integrated circuits, are hardware designed to do a specific task. In the case of Bitcoin, ASICs are designed to process SHA-256 hashing problems to mine new bitcoins. Ethereum, on the other hand, is designed to be mined with GPUs.
That’s because Ethereum’s mining algorithm, Ethash, is different from Bitcoin’s. Ethash is designed to be ASIC-resistant so that anyone with a GPU can mine it.
The main reason why ASICs can’t be used to mine Ethereum is that Ethash uses a different hashing algorithm than Bitcoin. Ethash is an “memory-hard” algorithm which means that it requires more memory to run than Bitcoin’s SHA-256 algorithm.
This makes it ASIC-resistant because ASICs are designed to be efficient at a specific task and don’t have the flexibility to switch tasks.
However, there have been some attempts to create an Ethereum ASIC. In 2018, Bitmain released the Antminer E3 which was designed for mining Ethereum.
But because Ethereum’s difficulty was too low at the time, it was not profitable to mine Ethereum with the Antminer E3. Bitmain has since discontinued the Antminer E3 and there are no other known Ethereum ASICs in development.
So while it is technically possible to create an ASIC for Ethereum, it is not currently profitable to do so. And even if an ASIC were developed, it would be quickly made obsolete by a change in Ethereum’s mining algorithm which has happened multiple times in the past.
For now, GPU mining is the best way to mine Ethereum and other memory-hard cryptocurrencies.