title: Swift Playgrounds working very slow
body: <p>I am using a few different SCNActions in my Swift playground and the animations run very slowly. 
  Here is an example of one of my actions</p>
  
  <pre><code>node.runAction(SCNAction.repeatForever(SCNAction.rotateBy(x: 0, y: 0, z:  2 * .pi, duration: 2)))
  </code></pre>
  
  <p>Also, my code for an action is in a separate class like I read online, so what could be wrong?</p>
  
  <p>Thanks in advance!</p>