I've noticed that even 60fps produces not perfect motion effect. Obviously it happens because 3d card produces snaps not frames, thus 60sps seems jerky.
Snap is an object instant image. On other side frame contains time interval image and dramatically improves perception quality of moving objects.
So, user is limited by 60sps, but if he tried to disable V-sync than he gets the same 60sps + tears. More graphic power wasted, more tears with the same motion quality. Vary bad.
Main idea is: accumulate snaps calculated while frame interval into one frame.
1. Work buffer. Holds currently generated 3d snap.
2. Snap buffer. Holds last completed 3d snap.
3. Accumulator. Contains sum of all snaps after last frame buffer flip.
4. Currently displayed frame buffer. Will be switched to 3, or 2 if there was no new snap or only one snap, or not switched if 2 is already taken.
Result: Triple buffer quality with sps below 60 and smooth motion above. GPU power not limited and not wasted.