title: RenderTransform takes too much CPU
body: <p>I have this Canvas in my xaml definition</p>
  
  <pre><code>&lt;Canvas Width="128" Height="128" Margin="10"&gt;
      &lt;Canvas.CacheMode&gt;
          &lt;BitmapCache /&gt;
      &lt;/Canvas.CacheMode&gt;
      &lt;Canvas.Triggers&gt;
          &lt;EventTrigger RoutedEvent="Canvas.Loaded"&gt;
              &lt;BeginStoryboard&gt;
                  &lt;Storyboard&gt;
                      &lt;DoubleAnimation 
                          From="0" To="360" 
                          RepeatBehavior="Forever" 
                          Storyboard.TargetName="spin" 
                          Storyboard.TargetProperty="(RotateTransform.Angle)" 
                          /&gt;
                  &lt;/Storyboard&gt;
              &lt;/BeginStoryboard&gt;
          &lt;/EventTrigger&gt;
      &lt;/Canvas.Triggers&gt;
      &lt;Canvas.RenderTransform&gt;
          &lt;RotateTransform x:Name="spin" Angle="0" CenterX="64" CenterY="64" /&gt;
      &lt;/Canvas.RenderTransform&gt;
      &lt;Image Source="Images\CircularLoading.png" Width="128" Height="128" /&gt;
  &lt;/Canvas&gt;
  </code></pre>
  
  <p>This animation takes 50% of my CPU, how can I improve the performance?</p>