title: Optimizing Cesium tile display performance
body: <p>for an interactive project I have created a Cesium viewer instance with two TileMapServiceImageryProvider intances which get their content from a fast local ssd.
  Howerver, the display performance when zooming in or out is not very smooth.
  It sometimes takes more then a second to display the new content. 
  I already turned the requestRenderMode on to increase performance of the whole project but I could ot find any way to speed up tile loading / rendering.
  Is there a way to optimize Cesiums tile-handling? Is caching an issue maybe? </p>
  
  <p>Thanks so much. </p>