load up cradle.lws and open imp3 window reset simulation erase all frames
press f in lw and tell to jump on frame 600, last frame is 600 by default when u run this scene.......
now wait and watch imp3 log window
on p4 2.4ghz
cradle.lws 17 secound
trampoline(mod2).lws 21min 19sec
here u can get faster calculation than pressing make preview hope it helps