How do I connect power to a NVIDIA GTX 1070 Founders Edition in a 2009 Mac Pro?

I am installing an NVIDIA GTX 1070 in a 2009 Mac Pro. I have seen all kinds of cables selling on Amazon and eBay to power GPUs in a Mac Pro so I want to make sure I get the right one.

Looking at the NVIDIA GTX 1070 manual, it looks like I will need an 8 pin connector on the graphics card side:

But there are cables that have this 8 pin connector with either one or two 6 pin connectors that will connect to the Mac Pro main board.

The cable I ended up ordering has 2 x 6 pins and 1 x 8 pin connectors:

https://www.amazon.com/gp/product/B0749DQ3VX

Will this cable properly power the GPU and should I connect both 6 pin connectors?

Solution 1:

You will need a Y cable with 2 x male mini 6 pins at one end and 1 x male 8 pin on the other end.

You will have to connect both mini 6 pin ends to the motherboard. 1 x 6 pin will not provide enough power. Only both 6 pin ends will be able to provide the power your GPU needs under full stress.