I guess if we are lucky it might run a little bit smoother, but unless they enable some DX11 specific features it's usually difficult to spot any difference.
If you have a radeon HD5000 series card the difference in performance between DX9 and DX11 is massive.
It's really disappointing that these cards run like garbage compared to the same price-point nvidia cards unless it's DX11
where they actually still only run as good.