PCI-Express 1.0 x16 vs. PCI-Express 2.0 x16 — is there a significant difference?

We all know that the difference in transfer speed on the pci-express bus has doubled, but is associated with a number of questions:

1) do All bus capabilities are used by modern graphics cards, or visible doesn't make any difference if you insert, for example, a GeForce GTX460 in the PCIe 1.0 and 2.0?

2) How to check the exact throughput? I found a PCIe Speed Test v0.2, but it works only on graphics cards from ATi

3) are There already motherboard with an honest pci-express 2.1, or the difference between 2.0 and 2.1 no?


I am interested in all this in the context of games, and in the context of CUDA