The S21 XP and M66S are the two dominant ASIC miners in 2026. One leads on efficiency. The other leads on raw hashrate. Here's the complete head-to-head — hashrate, power draw, ROI at different electricity rates, and which one actually makes you more money.
Electricity is the single biggest variable in Bitcoin mining profitability. This guide ranks all 50 US states by mining electricity cost, highlights the cheapest states, and shows you how to model your real ROI.