title: When does the CPU wait on the GPU?
body: <p>In an application which is GPU bound, I am wondering at what point the CPU will wait on the GPU to complete rendering. Is it different between DirectX and OpenGL?</p>
  
  <p>Running an example similar to below, obviously the CPU doesn't run away - and looking in task manager, CPU usage (If it were a single core machine) would be below 100%.</p>
  
  <pre><code>While (running){
  
      Clear ();
  
      SetBuffers (); // Vertex / Index
  
      SetTexture ();
  
      DrawPrimitives ();
  
      Present ();
  }
  </code></pre>