When I get these on 240 VAC the power supplies can supply 1200 watts each so I will switch to "High Efficiency Mode" which will pull power from only one supply and have the other in redundant very low power mode.
Wouldn't it be better to keep it on balanced and allow your PSUs to be more efficient?
It all depends on what the efficiency is at the load point.
Right now on 120 VAC my load is 815 watts which sometimes jumps to 825/835 watts. That number is really close to the 900 watt maximum that the 1200 watt power supply can produce at 120 VAC. Which is why I am running in balanced mode.
This is from one of my HP DL580 servers:
Power supply #1
Present : Yes
Redundant: No
Condition: Ok
Hotplug : Supported
Power : 390 Watts
Power supply #2
Present : Yes
Redundant: No
Condition: Ok
Hotplug : Supported
Power : 425 Watts
815 Watts total.
When this server is running on 240 VAC the power supplies can supply the full 1200 watts. So 390/425 watts of 1200 is only loading the power supply at 33-35% capacity whereas 815 watts of the 1200 is 68% capacity.
When I an on 240 VAC I will measure both the "High Efficiency" and "Balanced Mode" and chose the better one. If the "Balanced Mode" is only slightly better I probably will still chose "High Efficiency" so that only one power supply is needed and pull the other and keep it in case the first one ever fails.
This article gives an explanation of the differences between "load balancing" and "high efficiency" modes:
How do servers with redundant power supplies balance consumption?
https://serverfault.com/questions/659452/how-do-servers-with-redundant-power-supplies-balance-consumptionIt only has a chart for the 750 watt power supply not the 1200 watt power supply.