Thanks Jack for your quick reply!
We will make the animations more simple to reduce the CPU load.
We've already done some extra testing and came up with 2 more questions:
1. We've noticed in Safari, when a page has multiple animations, all the animations (also outside of the viewport) are loaded an stress the CPU. Is there an option to only start (and stop) animations when visible in viewport? This will help to reduce the CPU load in Safari.
-> This does not happen in Chrome and Firefox.
2. We've already tried to remove most parts of the animations only the CPU load in Safari keeps getting really high (about 60% on a 2,6 gHz i7 - Macbook Pro). Do you know what part of this animation stresses the CPU so much (especially on Safari)? So we can change or remove this part of the animation.