# How come if I am running a game at 300 to 400fps, and then cap my fps at 120 to keep it steady, my fps will now dip between 118 to 120? Shouldnt it never dip below 120 since it didnt before I capped it?

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How come if I am running a game at 300 to 400fps, and then cap my fps at 120 to keep it steady, my fps will now dip between 118 to 120? Shouldnt it never dip below 120 since it didnt before I capped it?

In: Technology

The computer takes the cap as a limit beyond which it won’t work. Previously if it finished one frame it would start on the next right away, but now it waits until the next frame is needed to reach 120 fps. Sometimes one frame might take a bit longer and it would fall behind.

Let’s illustrate this with a car. First I drive down the highway with no speed limit at all. I am now going say 85 miles an hour, but my actual speed varies from moment to moment. I go up a hill, it dip a bit, I go down and it goes up. So forth and so on. I still don’t go below 80, but it does go up and down.

But now I absolutely cap the cars speed so that no matter what I can’t ever go past 65. When I go up a hill, my speed will still dip a bit until I bring up the motor to comensate, When I go down a hill, I have to brake down lower than 65 to avoid going over. Various other things also happen. Even though I never went below 80 without a cap, I now am going as low as 60 or less at time, because having the cap doesn’t prevent the normal dips from happening and even causes new ones just in order to avoid the usual rises in speed that normally happen.

That’s basically what is happening with your system as well.