Using a PCI-E 2.0 card in a standard PCI-E 16X Slot?

Right now I Have a Compaq P4 3.2GHZ system with 1.5GB of ram. I want to get a better video card, but my mobo only has a PCI-E 16X slot in it, along with a few PCI slots in it as well. I was recently told that PCI-E and PCI-E 2.0 are backwards compatible and [...] http://bit.ly/pi9BmI