title: Poor StackPanel performance with WPF
body: <p>I have an application which runs fullscreen on a high resolution display (1920x1080).
  About 25% of the screen is a <code>StackPanel</code> that scrolls images across the screen.
  (the X position is animated with double animation)</p>
  
  <p>The scroll is very laggy and jumpy, and with visible tearing.
  This is running on a brand new high-end gaming laptop, running Win7 64bit.</p>
  
  <p>I don't understand why the performance is so poor. Am I doing something wrong? Does this kind of animation run on the CPU or GPU? Is there a smarter way to scroll images across the screen?</p>