> I didn't see a response from Gustafson to the latter accusation--the slide deck I see has him shifting from an argument about the power usage involved in sto

> I didn't see a response from Gustafson to the latter accusation--the slide deck I see has him shifting from an argument about the power usage involved in storing 64 bits of "unnecessary" precision to a commentary about the parallelizability of his approach (no comment about the work-efficiency!). Gustafson has addressed this. His argument essentially boils down to the fact that moving 64 bits to memory costs far more than doing the actual computation. Therefore, you have to spend more transistors doing the computation for unums, but you spend much less energy overall, since you have to transport less energy.