A Bitcoin miner can cut hashrate and still keep wasting power on work its pool barely recognizes. The issue is a vardiff controller that keeps assigning difficulty for the miner’s old speed after it slows down. If difficulty only updates when a share arrives, the miner can get stuck hashing against a target it now rarely reaches. https://cryptoslate.com/why-cutting-power-to-bitcoin-miners-can-actually-burn-more-energy/