Do the math, if a x16 lane gpu generates 300 mh/s ( based off an average mining gpu), a sound card whether on-board or plugging into a pci, pci-e x1 lane, or even pci-e x4 lane is not going to do f*ck all
numbers of pci lanes has nothing to do with mining
i have 5970 on pciex1 and it hashes with exactly same speed when connected into x16 slot