Hi, I've bought a XFX HD 7870 ghz edition online (link: http://www.dabs.com/products/xfx-amd-radeon-7870-hd-1ghz-2gb-pci-express-3-0-hdmi-dd-8VXW.html) and i'm really confused about what extra power needs to be plugged in. On the dabs website it says 1x6pin and 1x8pin but everywhere else i've...