How to set the fps/frame rate of a game?

It dips down from 60 fps to 45 fps when the banner either loads or an animation on the banner plays, but when I set the target frame rate to 30, it fixes the lag from the banner ad but 30 fps makes the game look way too choppy, so I want to try to set it to 45 but when I set it to anything above 30 it puts the fps at 60.