Most Power-Efficient ASIC Miners

Hashrate determines your revenue; J/TH determines how much of that revenue survives the electricity bill. A 5% efficiency gain usually beats a 10% hashrate gain once electricity is factored in.

For SHA-256, anything below 18 J/TH is competitive and below 12 J/TH is leading edge. Lower-hashrate algorithms use different units — look at the per-algorithm efficiency ranking rather than cross-algorithm absolute numbers.

Usually yes, if your electricity is above $0.05/kWh. Run the payback calc on the product page with your real rate — efficient flagships typically break even faster than mid-tier alternatives when power costs are real.