Hello,
I am preparing to switch my 4GB rigs to Linux based OS, but have this situation as described in subject.
9x470 GB on Win10 gives me 262MH/s @ 1050W on the wall. HiveOS with same OC, and downvolting gives less with much much higher consumption - 259MH/s @ whooping 1350W and cards are very hot. What I am doing wrong? Maybe there is any tricks to lower consumption?

Those who wrote above, they simply don't understand or don't know how to achieve this in Hive OS.
You can get exactly the same consumption as Windows or so.
My 8 card rigs consume about 1100 W from the wall by wattmeter (+/- 50W)