I upgraded from an x79 board where there was a free pci slot above my sound card, but now my sound card is stuck in between two video cards on my z87 deluxe board. Now whenever I watch or listen to stereo, my sound channels would suddenly shift to my rear speakers or to my center speaker every two or three minutes. I even switched my Xonar DX out for another identicle Xonar DX and it still does the same thing. I also tried sitting it on the top pci-e x1 slot and still no luck. I need some help please on what is causing the sound channels to shift on this z87 board.