title: Grand Central Dispatch async vs sync
body: <p>I'm reading the docs on dispatch queues for GCD, and in it they say that the queues are FIFO, so I am woundering what effect this has on async / sync dispatches?</p>
  
  <p>from my understand async executes things in the order that it gets things while sync executes things serial.. </p>
  
  <p>but when you write your GCD code you decide the order in which things happen.. so as long as your know whats going on in your code you should know the order in which things execute.. </p>
  
  <p>my questions are, wheres the benefit of async here? am I missing something in my understanding of these two things.</p>