PSU comes with 2 x 6 pin PCI-E and 2 x 8 pin PCI-e connectors . My GPU's have 1 8pin and 1 6pin connector. For some reason 6pin cable wont come into GPU - it looks like it doesnt fit inside. I tried to connect also 6 pin to 8 pin adapter cable to this PCI-E connector but it wont connect either. This cable goes fine on my other PSU's .
I saw on thermaltake URL that this PSU is Nvidia SLI certified .
Please look at your cables. The six pin pci-e plugs with the clip facing up have two round bottom and one square bottom connector on the top row and a square bottom and two round bottom connectors on the bottom row. Match the patten socket on your gpu. If it does not fit in, turn it upside down. The other possiblity is you are trying to use the wrong end of the cable.