yes all the pci express slots are backwards compatible, pcie 3.0/2.0 card works on pcie 2.0/1.1/1.0 slots
so it will work
but i read in some blogs that amd/ati cards might have backward compatibility issues which may depend on the mobo. although i have used nvidia 9500 gt (pcie 2.0) in my 1.1 slot.my doubt is about amd/ati cards...