your psu in conjunction with the mainboard takes a long time enumerating the hardware?

i honestly can't imagine how the power supply unit would make the slightest difference to hardware detection. the initial power needed to boot and spin up all drives maybe, but not 'enumerating'.

that said, i've seen my own theme grind to a halt on random systems, only loading as far as lsxcommand.

try commenting out modules in your theme one by one. when you find the culprit(s) maybe email the authors and tell them what's going on.