Question Powering 14-pin GPU with 1 cable that branches from single 8-pin connector on PSU into 2x (6+2) pin connectors on the GPU?

[pcbuildingrookie]

I bought a new GPU (Sapphire Nitro+ RX580) that requires 14-pin (8-pin +6-pin) power. My old GPU only required 8-pin power, but the cable that was hooked up to it branches from a single 8-pin connector on the PSU to 2x (6+2) pin connectors on the GPU end. My question is, can both of the 6+2 pin connectors be plugged into the GPU despite there only being one 8-pin connector on the PSU? Or do I have to use 2 separate cables?

 

[norcalsc]

what PSU do you have?

 

[pcbuildingrookie]

EVGA SuperNOVA GS 550 W