I have tried Asphalt 5 3.0.8, 3.0.9, 3.1.3 and they run very, very smooth, but the boost button does not work. When I use 3.1.8 and 3.1.9 the boost works, but it is somewhat choppy. Not bad, but enough that I would rather use the earlier version if I could figure out why the boost is not working. The button lights up when you touch it, but nothing happens. Im running it on a Samsung Captivate with 2.1. Anybody else experienced this? Thanks!