Bernstein, a research and brokerage firm, rated Riot Platforms, CleanSpark, IREN, and Core Scientific as "outperforming" in its Bitcoin mining report released today, while Marathon Digital was rated "market performing". The evaluation is based on five key metrics: production and hashrate, operational and energy efficiency, electricity, hashrate cost, and artificial intelligence strategy. Core Scientific leads in hashrate cost and AI strategy, while CleanSpark and IREN perform well in energy efficiency. Riot lags slightly in production and efficiency, but makes up for it with power credits and improved production efficiency. Marathon improved operational efficiency by switching to proprietary mining.