title: ng build -prod vs ng build --prod --build-optimizer=true
body: <p>My Angular project is @Angular4.3.3</p>
  <blockquote>
  <p>ng build -prod</p>
  </blockquote>
  <p>Takes 77 seconds to make a build</p>
  <blockquote>
  <p>ng build --prod --build-optimizer=true</p>
  </blockquote>
  <p>Takes 190 seconds to make a build, No vendor chunk, less in size(but not a big difference in size though)</p>
  <p>Chunk differences on console image:
  <a href="https://i.stack.imgur.com/5AhUm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5AhUm.png" alt="Difference between those two builds" /></a></p>
  <p>I read <a href="https://github.com/angular/angular-cli/wiki/build#bundling--tree-shaking" rel="nofollow noreferrer">Bundling &amp; Tree-Shaking</a> but still don't get the clear difference between builds created by those commands.</p>
  <p><strong>Why there are these two different ways and what is the difference in performance or any other way?</strong></p>