If a card is compatible with PCIe Gen 3 then it's also backwards compatible with the other generations.
Only the newer motherboards post 2011 have gen 3 compatibility.
PCI 3.0 = two times the bandwidth of PCI 2.0
x16 = how many connectors you PCI slot has, which in this case, is the most.
Need someone with a nVidia GFX card, Visual Studio and some debugging knowlegde