Installing S9170 in a Dell PowerEdge R720. Do I need both 6 and 8 pin power adapters connected? Not sure why I cannot locate more specific instructions.

I just purchased this S9170 to test on my Win7 VDI XenDesktop environment.

 

The instructions are vague using term (as applicable) in the Connecting Supplementary Power section.

 

Do I get these cables from AMD or Dell?  Thanks for any assistance you can provide.