the 3d demo on wintermute don't use the new quicksave parameter for save games, but there are a problem with save games with wme 1.10.1. here you can see the specification --->http://forum.dead-code.org/index.php?topic=5221.0
i don't know if this problem affect the 3d demo proyect.
in the new version, there are a new parameter named QuickSave that no exist in old version, and the 3d demo project is older, maybe its hasn't got this parameter implement in the proyect...
i dont know about the difference between save on window, and save on full screen, maybe its the screen size.
for this maybe, its can take many time the 3d proyect to save, than new projects with the quicksave parameter.. but only its a supposition.
See the wme 1.10.1 specification on the web before and maybe you can find the answer of time for the time to save games.
i recomend you that create a new proyect with the quicksave parameter implemented and test it..
sorry for my english...XD