What is the difference between PCI Express 2.1 x16 and PCI Express 2.0 x16 graphics card?

Im not super amazing at computers, but I was curious whats the difference was. I'm looking at buying a new computer, but the one I'm looking at says the card included with it is PCI Express 2.1 x16. However the one I currently have in my computer I know is a PCI Express 2.0 x16 slot video card.|||PCIe 2.1 runs at the same speed as 2.0, but has several "beta features" (for lack of better words) to be included in PCIe 3.0.