As long as your GPU isn't so big that it overlaps the other pci ports you should definitely be able to fit a sound card in there. Your mobo comes with 5.1 onboard sound, so here's a 7.1 that seems decent. http://pcpartpicker.com/part/asus-sound-card-xonardsx
So can u tell me what is the difference between pci x16 and normal pci 2.0 slot and in which slot I will insert my sound card because I have already inserted graphic card in my PCI x16 slot