Question Graphics card power cables?

[Gojke]

Hello, I'm unsure and have a few questions?
I bought a Thermaltake Toughpower GF1 ARGB 750W power supply, my graphics card is powered by 6 + 4 cables.
This is what the connector side looks like:

And I have 2 cables that split for PCI-E, and they look like this:

I was informed that it is more correct to use 2 cables for graphics, and not to split over one.
My question is:

The one I don't know what it's for, do I need to connect another graphics cable to it?
I'm not sure, because it doesn't say above the connector if it's for that?

 

[Eximo]

Yes, that is your second CPU/PCIe port. They are both 12V only cables, just the pinout on the other end that is different.

 

[Gojke]

Thanks a lot, I thought it was just for the motherboard, because it says so above.