They aren't slow on my macbook/chrome (which is a bit older than that). Are you speaking of the actual timing of the animation, or the framerate? If it is the timing, that can be adjusted. For instance, in the css you'll find things like:

transition: -webkit-transform 500ms;

transition: transform 500ms;

Just change that 500ms to 200ms and it will take less time. The effects will be more subtle (so maybe not as good for "showing off" as in the demo), but probably a better experience.

Macbook 2012, Safari an it's super slow too ;-(