Will a PCI Express 2.0 card work in a PCI Express x16 slot?

I'm building a little gaming machine for myself and I bought a NVidea GeForce XFX 9800 GTX 1 Gig Video Card PCI Express 2.0, but I later realized that my PCI slot on my motherboard is of the PCI Express x16 type... my question is: Will the PCIE 2.0 card work in the PCIEx16 slot?|||It's all explained in the MoBo User Manual.|||Yes you can that card maybe a PCIe 2.0 but it still runs at x16. My 9600gt is a PCIe 2.0 card and it works 100% in my PCIe x16 slot.|||yes u can.. and vice versa as well ...and to further prove it i am useing two geforce 8800gts 512 in sli on a pci-e 16x mobo and they are both 2.0 cards =)|||Yes, pci-e 2.0 is completely backwards compatible.