Antminer S21 Series — The Most Powerful Miners on the Market in 2025
As the year draws to a close, the profitability record undoubtedly goes to the Antminer S21 series, which marks a new stage in the evolution of Bitcoin mining machines.
Its most powerful model is developed by Bitmain: this generation reaches a computing power that can exceed 245 TH/s, with an energy efficiency of around 15 joules per terahash — a record for the industry.
This model illustrates the current trend: ever more powerful machines that are also more energy-efficient. In practice, this cuts electricity costs while maintaining a high level of security on the Bitcoin network.
However, users should consider several factors before any purchase:
• the quality of the power supply,
• the ambient temperature,
• and the cost per kWh in their region.
The Antminer S21 has now become an interesting case study in energy optimisation in mining.