https://www.moddiy.com/products/Apple-Dual-Mini-PCI%2dE-6%2dPin-to-Standard-PCI%2dE-8%2dPin-Video-Card-Cable.html
https://www.ebay.com/itm/CPU-8Pin-to-Graphics-Video-Card-Double-PCI-E-8Pin-6Pin-2Pin-Power-Supply-Cable/202192838844?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
this is what i used on my MAC
Thanks, bro!