Yea two power supplies will work either with this add2psu or paper clip method but I am curious about the power consumption, will using two power supply draw same energy as using one power supply? Would using two draw more power?
Better to use one power supply. The more power supplies, the more power losses, but they are not so big. This is the efficiency and cooling of each power supply.
For example, if you need a 1500 watt power supply and you do not want to use a server power supply, then it is better to buy 2 power supplies of 850 watt each, because it is cheaper.