Is there a firmware version that has low power mode?  I have only seen Performance and Normal.  Canaan really did a disservice to their customers by limiting the available commands.  For all of the faults with the 84X model, you could safely run them in 110F temps by backing them down and then overclocking them in the winter.  The 1047 model chews through PSUs, we don't even run their newest firmware because of that reason.