$ plug molex connector on a evga 680i a1

I have the evga 680i a1 mb and will be running a msi 8800 ultra, but at this time no sli. There is an axillary 4 prong molex connector on the mother board that the manual lists as for added graphic card power. I have a thermaltake thoughpower 650 w with more than enough pci-e power cennectors for the graphics. Do I also need or should I use this additional 4 prong mb plug?