Is it safe to frequently restart an ATX power supply
If you have your mind set on power cycling the Arduinos, why not do the following? This way you don't have to restart the whole PSU.

Make sure you get a FET that can handle all the Arduinos (or you can use one FET for each Arduino).







simulate this circuit &ndash; Schematic created using CircuitLab

Another solution that ocurred to me is.. why not control the ATX PSU the same way computers motherboards do?

Put a FET/relay (or even control it directly as per this tutorial) between the Pwr_On and GND pins (on which I believe you must have some jumper if you are using ATX PSUs).



So.. not many external components, the problem with inrush current in the input caps is gone, and.. you got the power cycle you wanted.