Running at Max settings at WQHD (2560x1440) resolution, I have definitely noticed a difference in the visuals. Yes, there are some odd things that happen like the ground seeming to slightly ripple when moving quickly across it but overall I would say its a discernible improvement.
P.S. For greater visual improvements, make sure to go into your graphics card settings and increase the color bit depth. For me it greatly increased the richness and color palette of the game as well as improved the visual contrast and shadow detail. This is independent of the dx version you are running.