it s maybe restricted to 75w but it use more
i have 5x rx460 4G msi with no pci-e power and with dual mining the ring use 560w (no cpu load) with stock setting
so you can say each gpu use 100w
i would be very surprised if a 460 with no pcie connector used more than 75 watts, even dual mining. 100 watts is WAY over the pcie spec.
60 watts for the just PC? seems kinda low unless you are using a "T" series intel proc, single ram stick and a m2 drive (and nothing else, including no fans).
my pc at idle uses 80-90 watts at the wall. g1840 proc, 2x4 gb ram, 390, 2x470, 460, 1070. 256 gb m2 ssd, 5 fans. evga 850 g2 gold psu pulling 750 at the wall mining only eth (dual mining pushed it to over 900 watts at the wall) (still need to tweak some stuff, hope to lower it a bit). all this on measured on a killowatt meter. 120 volts power.
doesn't matter if idle computer use 60 or some more even if it s 100w so it still 92w per pci slot the gpu use