CrimsonLuke :
DasHotShot :
You definitely see the difference in many games, in others it makes little to no difference.
And no, the 25 FPS thing is no myth, it's your eyes.
So why can we differentiate between 24 fps and 60 fps?
A 24fps movie, can look far smoother than a 60fps game...So much so I believe I could trick you into believing the lower fps movie was running at a far higher frame rate than the game.
Imagine yourself watching a movie featuring unbelievably slow fog. You don't see edges and sharp borders. Now play the movie at 10fps. It will look fluid. Why? Because the difference from one frame to the other is very low. The extreme would be a totally stationary wall: Then 1 fps would equal 1000 fps.
Now take your hand and move it slowly in front of your face. Then move it faster until it's blurry. How many frames per second do you see? It must be very few, because you only see a blurred hand without being able to distinguish every change per millisecond, but it must be loads, because you see fluid motion without any interruption or jump. So this is the eye's trick in both examples: Blurring simulates fluidity, sharpness simulates stuttering.