I have already tried the 320.18, i have heavy stuttering with them, last stable driver release for me is the 314.22.
In the last days, i have found a official nvidia news ...(they had a huge improvement to vsync code for the 600 nvidia series, near to may of the last year and the 320.18 is the first driver to incorporate this upgrade). So for me, they have broken something.
Now i have found a partial fix and i can use the last nvidia driver .... if i use under opengl full vsync, i still have stuttering, but if i adopt adaptive vsync i have a smooth scroll. (i dont know the why, but at least it seems to work for now).