I would know what is of cable I have to use to connect the 4pin molex to a power supply ? Which reference is it ?
I don't get it what you are trying to ask. I will try to explain with a simple explanation. Usually, PCIe 1x would be giving about 25 Watt to our cards, if only three cards, 8 Pins CPU power can handle it but if we put more than three cards, we need more power so that two Molex connector required. And you can use two Molex connectors from your PSU.
don't hook up those 4 pin floppy molex plugs, its NOT needed since the lot of us use POWERED risers, the molex plugs are for if you are using NON-powered risers, under certain conditions you can fry you gpus if you have those plugged in on the mobo, those plugs are for supplemental power to the gpus from the mobo, I have this very motherboard, I even have the older revision before r2.0 neither of which have the 4 pin molex connected to the mobo