This 6-Pin Male to 8-Pin Male PCI-E 2.0 Adapter Cable is for Modular ATX Power supply with 6-Pin PCI Express slot. It is designed to convert 6-pin PCI Express to an 8-pin PCI Express. The 6 to 8-pin PCI-E adapter is ideal for newer video cards that need the new 8 pin PCI-E connector and for those with older generation PSUs.

This is used to connect a 8-pin PCI-E power with only 6-pin PCI-E slot on the power supply, normally PS is at least 500W to qualify for the conversion.