power supply - Is there a difference between 8-pin EPS12V and PCI-E connectors? - Super User
Amazon.com: COMeap 8 Pin Male to Dual 2X 8 Pin (6+2) Male PCI Express Power Adapter Cable for EVGA Power Supply 25-inch+9-inch (63cm+23cm) (NOT Compatible with Seasonic Sentey and Corsair Power Supply) :
Test your power supply with a multi meter | Tech Support Forum