title: lagging when scrolling
body: <p>I'm using core-plot in my iPhone app to display datas in plots from NSMutableArrays.
  I display 10 values on the screen and I allowed horizontal scroll only like that I can see all the values when I'm scrolling.
  I've got something like 100-200 values in total to load.
  I use differents tabBars to handle my differents needs.</p>
  
  <p>Everything works fine, but when I launch my app on the iPhone I have some monstrous laggs when scrolling. Something like 2 seconds after the graph move (on the simulator there is no laggs).
  I reload graph when I shake the iPhone.
  I work on a 3GS, and there is no other app running in background.</p>
  
  <p>Did someone had and resolved something like that?</p>
  
  <p>Do you need more info?</p>