I Agree with Rajiv Doolub because cards now a days are having a backward compatibility even they are PCI-E 2.1.
Probably,The Intel DG41RQ will support almost every graphics card but remember you need a powerful Power Supply Unit (PSU) if you are buying any graphics card.
On the other hand it can even handle a HIS HD 5770 GPU or a XFX nVidia GTS 250 or the GTS 275.
so can it run a pcie x16 2.0 and pcie x16 2.1 graphics cards??
like a axle HD5670???