Your motherboard, or any other motherboard in the world which has a PCI-E slot, will support ALL types of PCI-E GDDR X cards.
GDDR is completely different to DDR.
GDDR is the memory on the graphics card, which has no effect on the motherboard
DDR is motherboard Memory. This does have an effect on the motherboard. Meaning DDR wont fit into DDR2, or DDR3 into DDR etc..
Hope this helps