http://forums.guru3d.com/showthread.php?t=360154

to reduce input lag in BF3 with vsync enabled, use a user.cfg or bf3 settings editor to cap your framerate to one fps less than your screen refresh rate, and then DISABLE triple buffering as well. (which is strange because normally triple buffering is recommended to be used with vsync, and BF3 enables it by default)

worked great for me.

This works for most games, in Valve games I use 59.9 fps lock to stop lag when using vsync.