I usually notice input lag in first person shooters when I have V-sync / fast sync on. V-sync introduces about 1 frame of input lag (0.5 frames for fast sync),

I usually notice input lag in first person shooters when I have V-sync / fast sync on. V-sync introduces about 1 frame of input lag (0.5 frames for fast sync), so 8~16ms is just enough to throw myself off. I would guess platformers and fighting games would have similar kinds of input lag problems.