Hey there,
 
I was wondering... as the 970 has two 6-pin ports on it for power should I use the cable with 8-pin (from PSU) to two 6-pin connectors or should I use two separate 8-pin to 6-pin cables to power the GPU? ... or does either work?
 

This is the first one which I would use just this one cable.
 

and this is the second, which I would have to use two of.
 
The only thing I don't like about the first cable is that the because each of the 6-pins has a detachable 2-pin part (why, I've never seen a GPU with 8-pin for power..) I have to have both folded back to the side and I feel like it causes some stress on the power ports when plugged into the GPU.
 
Thanks in advance for your help.

I thought it might work either way, but I just wanted to make sure that either using one cable'y' type cable so to speak didn't provide a shortage of power, or using two separate cables gave too much juice.

Never Use A "Y" Cable when it come to PCIe Power.
Most PCIe Power Cables come with One 6+2 Pin or Two as what the OP has or One 6+2 Pin and One 6-Pin.
You can use One Cable with Two Connectors or Two Cables and use one Connector from each cable.
The Y cable that comes with a card are for users who DO NOT HAVE 6-Pin PICe Power Connectors.
They are used to connect Two 4-Pin Molex Power Cables to make ONE PCIe 6-Pin Power Cable.
I have Graphics Cards that use Two 8-Pin Power Cables as well as some that use One 8-Pin and One 6-Pin PCIe Power Cables.
 

This computer has 6 Each 6+2 PCIe Power Cables connected to 3 Graphics Cards.
Each card uses 2 Each 6-Pin PCIe Power Cables.