Acording to this pic :
You have 2 PCI slots. Even with 2 graphic cards, you should be able to use the first one (the one on the right). Or are you using both?
Please excuse my bad English.
Currently gaming on a PC with an i5-4670k@stock (for now), 16Gb RAM 1600 MHz and a GTX 1070
Steam / Live / NNID : jonxiquet Add me if you want, but I'm a single player gamer.