[glowx]

The manual specified for this:

"ATX4P (PCIe Power Connector)
The power connector provides auxiliary power to the onboard PCI Express x16 slots. When two or more
graphics cards are installed, we recommend that you connect the SATA power cable from the power supply
to the ATX4P connector to ensure system stability. For 4-way CrossFireX™/SLI, you must connect the ATX4P
connector."

I am currently using only a single GTX670.

Does anyone know whether there might be any enhancement from hooking up this ATX4P anyhow. Might this extra power harm the mobo or GPU or just have no effect at all?

 

[ripsaw]

no, no and no

 

[svenge]

It shouldn't harm the motherboard / PSU / etc. to hook it up even with a single video card. Still, since you don't need the additional power just leave it be until you actually have 2 video cards in it.