ASICs, or application-specific integrated circuits, are chips designed for a specific purpose, such as mining Ethereum. ASICs are more efficient than general-purpose GPUs, which is why they are often used in Bitcoin mining.
Ethereum does not currently allow ASICs. Ethereum’s developers believe that ASICs centralize power and threaten the Ethereum network’s security and decentralization.
They have suggested that Ethereum may eventually switch to a proof-of-stake consensus algorithm, which would make ASICs obsolete.
In the meantime, Ethereum miners can use GPUs, which are more widely available and less expensive than ASICs. While GPU mining is less efficient than ASIC mining, it is still profitable for those who are willing to invest in the hardware.
The conclusion is that ethereum does not allow asic but may in future.