Motherboard: Asus A88X-PRO
APU: AMD A10-7850K (monitor only receiving R9 Nano output)

I will update the bios and see if there are any "new pcie gen or generic pcie
performance options".

I report back on the use of "amdgpu.pcie_gen_cap=0x00030003" in lilo although 
"PCIe 3.0" is printed on the motherboard.