The problem of speed is, as a rule, do not ease the implementation of roundabouts, but rather in its use. Often had to deal with this challenge and here's a few tips on speeding up:
1. Try to use images of the smallest possible size.
2. Try to use the least amount of images, no need to make a huge sheet of tens of thousands of pixels.
3. Try to avoid asynchronous requests to the server during the animation.
4. Increase the animation time and interval.