he is saying that PCI express 1.0, 2.0 and 3.0 are all compatible with each other so in theory you should be good to go. However a there was a lot of issues popping up where the BIOS wasn't compatible with the newer graphics cards, something about UEFI. I am not sure, but clutchc may know something more about it.
Keep in mind that CPU will be a significant bottleneck for modern games and there is really nothing you can do about it except build or buy a more modern PC. My last PC had a Phenom II x4 820 and I put a R9 280 (very similar to the 1050ti) in it. It helped over my 8800GT but it held back the graphics card from working at its potential.