Same GPU here but lower resolution (1360 x 768), and an i5. No stuttering over here. I run everything on ultra except FXAA for the anti aliasing. My drivers though are 355.82. I don't play much in the way of modern titles, so I don't really feel the need to update unless it's to fix an issue.
The DOF seems to be working on Ultra, though it is much more subtle than with the normal setting. The intent behind DOF isn't to overly-blur details, but to attempt to convey a sense of grandeur to the environment.