> more efficient (hashes per watt) than general hardware That's not the only relevant measure, since specialist hardware must be designed and produced. For a

> more efficient (hashes per watt) than general hardware That's not the only relevant measure, since specialist hardware must be designed and produced. For a memory-latency bound PoW requiring hundreds of MB, it's far from certain that custom designed RAM can compete with commodity RAM. For instance, SRAM is one order of magnitude faster than DRAM, but two orders of magnitude more expensive, making it much less suitable for mining.