If I'm correct, that cable on the right of that pic is an 8 pin PCI-e cable. It looks like a 6 pin cable, but there are two extra pins on the side that look separate, but they go with the 6 pins to make 8 pins the same way your CPU power connector is probably two 4 pin connectors. http://imgur.com/xzeZFDB
Those both look like 6+2 power connectors to me and should work fine. Get rid of those adapters and try those out.