Rainbow background on : 9-8 FPS
When the ball is in the "bottom" : slight acceleration, the counter goes to 11-12 FPS, but it feels more fluid.
Without rainbow background : 23-30 FPS
When the balls in the "bottom" : slight acceleration still FPS goes up to 43.
Without rainbow feels a lot better/fluider as soon as it is set.
On both, the red rounded rectangle make a a slight lose of FPS (down to 19 instead of 23-30 without background) and there is an offset in the moving (the red rectangle is "a second behind" (not a full second)).