On Figure 15 you can see this power supply label containing all its power specs. You can clearly see that the manufacturer says that the maximum power this unit can deliver is 610 W (591.5 W + 18.5 W), not 660 W. Pay also attention as the “660” on the top right corner does not have a “W” after it.
click to enlarge Figure 15: Power supply label.
As you can see this power supply has three +12 V virtual rails, distributed like this:
+12V1 (solid yellow wires): Main motherboard cable, peripheral and SATA power plugs.
+12V2 (solid yellow wires): The two ATX12V connectors, one of the video card connectors.
+12V3 (yellow with blue stripe wires): The second video card power connector.
We think that this distribution is adequate, but AcBel should have labeled the video card power connector that is connected to the +12V3 rail with a label to indicate that this the main and preferred cable for you to connect your video card, if you have just one video card on your system.
Let’s now see if this power supply can really deliver 610 W of power.