I have a computer with a PCI 2.0 x16 video card slot. Does PCI 2.1 work too?

I am planning to get a new video card, mine is pretty much shot. Planning on getting a: Radeon HD 6870 1GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity Will it work in a MOBO with PCI 2.0×16? or do i need to get a new MOBO? http://bit.ly/nzJaXS