I think I understand what's your means about the smooth in the other topic.
As below is the sample code about how to use PreviewTileCache:
winformsMap1.ThreadingMode = MapThreadingMode.Multithreaded;
FileBitmapTileCache cache = new FileBitmapTileCache("YourCacheFolder", "world");
WorldStreetsAndImageryOverlay worldOverlay = new WorldStreetsAndImageryOverlay();
worldOverlay.PreviewTileCache = cache;
Wish that's helpful.