I recently purchased a ELT500AWT 500W Liberty PSU with the modular cabling. This came with two cables for the PCI Express video cards. Both cables have 6 pins at each end. The power connection on my motherboard for the PCI-E is a standard 4 pin connection like one that powers a hard drive. The motherboard is a Gigabyte GA-M57SLI-S4. Is there an adapter I need to convert the 6 pin to a 4 pin? Or can I use one of the 4 pin connectors labeled for HDD/Peripherals?