Not sure about this, I know from my CoD 4 days that the FPS was locked at under 90FPS
Now unlocking the FPS in CoD 4 (I used to play mine on 250fps) enabled you to do things in game that were not possible on sub 90fps settings (which is why a lot of servers would kick you if you were using fps settings over 125fps)
An example was the concrete blocks, you couldn't just jump over them on sub 90fps, but over 150fps, you could jump over them without being hindered. It also enabled you to reach some places that you couldn't reach otherwise.
I honestly don't know how having a higher fps rate in that game enabled you to jump higher, but it worked, and for a lot of people. Also, I haven't experienced a difference in any other games.
I would like more info on the fps rate against hz as my monitor is a 60hz, yet I am able to get fps rates much higher than 60 (using fraps or ingame fps monitor its the same, on older games, I can get extremely high fps rates)