Using the molex-modified PCIe x1 cables, and they work so far. Now I'm at the maximum of my PSU and will order a new one. Just a quick question: is it save to power a card on another PSU than the others? I basically have 3 cards already all on 1 PSU, and the fourth will be on PSU #2, and connect its 6/8-pin connector and its molex to this PSU.
Could there be a problem or am I on the safe side?
It's not safe, but it can be done.
Short a Green and Black wire on the 20/24 pin ATX connector using a paperclip shaped like a U. Hook up graphics card. Try to figure out the exact timing of turning everything on. It needs to be near simultaneous, but not quite. Basically a few milliseconds after the main PSU starts the dedicated one needs to be switched on.
Although not all PSUs will power on like this, some need a constant draw device like a case fan hooked up to a molex connector.