Having the physics simulation run asynchronously from the main loop is not currently supported.
If you don't mind the tearing, you can disable vsync to have the main loop run as fast as possible:
If you would like to disable vsync, but still set a limit on the frame rate, you can use the
viz.max_frame_rate option:
Code:
#Set max framerate to 120
viz.setOption('viz.max_frame_rate',120)