Can I use this PSU cable backwards?

Hi, my bitcoin miner just arrived and before I plug it in, I wanted to know if I can use a cable backwards. The miner uses 6 pin but I believe you are supposed to use the 8 pin output from your PSU. My Corsair PSU came with 1 cable that goes from 8 pin to 6+2 pin, but I needed more than one, so I borrowed one from my friend that has a gray 6 pin that goes to a 6+2 and 6 pin. I want to use the 6+2 in the PSU and the 6 in the miner. Sorry if I sound like a retard. I'm very ignorant when it comes to PSUs.

Cable I want to Flip:

Miner:

Stock PSU cable:

An extra question: Am I doing anything wrong if I plug in both 6 pin connectors on the stock cable? I was thinking of doing that so less power is flowing through each "rail" of the miner. Thanks.

Should explain everything you need. If you are at all concerned or unsure just grab a dual molex to 6pin adapter ~ few cents or hunt around in a bin outside you local pc store.

+1.  I also would never use another cable from a different power supply.   just grab a dual molex to 6pin adapter

So you're saying you want me to use this:

And connect it to that? If so, why? Once again, derp. Thanks

And what's the problem with using a cable from a different power supply?

 

 

 I also would never use another cable from a different power supply

Theres no harm in that. The wires are all the same. They arent special. They're (mostly) all wired the exact same way. you will never have two modular cables from different manufacturers that put different voltages through different wires. Because all 6 pins, satas, and everything require the same amount of current through the same wires, respectively.

So do you think I can use the cable that my friend gave me without a problem?