Antminer S21 series — The most powerful miners on the market in 2025
30 Oct 2025
At the end of this year, the profitability record is undoubtedly attributed to the Antminer S21 series, which represents a new stage in the evolution of Bitcoin mining machines.
Its most powerful model is developed by Bitmain; this generation achieves a computing power that can exceed 245 TH/s, with an energy efficiency of around 15 joules per terahash, a record for the sector.
This model illustrates the current trend: increasingly powerful machines that are also more energy-efficient. In practice, this reduces electricity costs while maintaining a high level of security on the Bitcoin network.
However, users should consider several factors before making a purchase:
• the quality of the power supply,
• ambient temperature,
• and the cost per kWh according to their region.
The Antminer S21 is now emerging as an interesting case study on energy optimization in mining.