After some tweaking, 128 turned out to be the most smooth version ever... for me, at least. For example, at the airfield on the ground, I used to see 35-45 fps. Now it runs at almost constant 60 fps (with vsync turned on).
The only issue seems to be that whenever there is an explosion near me, the motion freezes for a fraction of a second. This problem has been there, but it seems more serious in 128.
I'll make a few screenshots of my settings, in case that could help some people here.