All cases are MultiTile mode.

no cache(with kml) 
ZoomLevel4 drawingtime:6702.5349
ZoomLevel5 drawingtime:5006.6129
ZoomLevel6 drawingtime:3858.1073
ZoomLevel7 drawingtime:2879.8361
ZoomLevel8 drawingtime:3973.3478
ZoomLevel9 drawingtime:3705.2631
ZoomLevel10 drawingtime:3149.5966


No Cahce, No kml
ZoomLevel4 drawingtime:3260.8541
ZoomLevel5 drawingtime:4845.9317
ZoomLevel6 drawingtime:2470.5858
ZoomLevel7 drawingtime:1015.5698
ZoomLevel8 drawingtime:2343.3783
ZoomLevel9 drawingtime:1477.3631
ZoomLevel10 drawingtime:376.1924

cache(with kml)
ZoomLevel4 drawingtime:158.1404
ZoomLevel5 drawingtime:214.6851
ZoomLevel6 drawingtime:229.6523
ZoomLevel7 drawingtime:206.2937
ZoomLevel8 drawingtime:238.3399
ZoomLevel9 drawingtime:241.2676
ZoomLevel10 drawingtime:225.0435


no cache, kml in different order

WpfMap1.Overlays.Add("kmloverlay", kmloverlay)
WpfMap1.Overlays.Add("WorldOverlay", WorldMapOverlay)
ZoomLevel4 drawingtime:3438.5239
ZoomLevel5 drawingtime:4901.7251
ZoomLevel6 drawingtime:2456.5653
ZoomLevel7 drawingtime:1007.3429
ZoomLevel8 drawingtime:2650.6194
ZoomLevel9 drawingtime:1622.7677
ZoomLevel10 drawingtime:467.1412

WpfMap1.Overlays.Add("WorldOverlay", WorldMapOverlay)
WpfMap1.Overlays.Add("kmloverlay", kmloverlay)
ZoomLevel4 drawingtime:6750.6154
ZoomLevel5 drawingtime:4850.7554
ZoomLevel6 drawingtime:3058.2372
ZoomLevel7 drawingtime:1397.4943
ZoomLevel8 drawingtime:3146.0003
ZoomLevel9 drawingtime:2456.8363
ZoomLevel10 drawingtime:799.0147