title: cocos2d Not running on 60 FPS WITH FIXED TIMESTEP
body: <p>I'm running on 40 FPS on my iOS cocos2d app with 80 Box2d objects. I'm using fixed timestep:</p>
  
  <pre><code>-(void) update: (ccTime) dt
  {
  if( gameState_ != kGameStatePaused ) {
  world_-&gt;Step(dt, 6, 1 );
  
  ....
  }
  </code></pre>
  
  <p>Why is that happening? Thanks.</p>