Indeed on SSD i noticed things load quickly, however on none SSD drive i myself noticed a long loading time almost equalling to hanging when loading a particular save game for the first time, however subsequent loads of the same game were quite quick, so i am sorry i do not thing i can do much about it, i save quite a lot of data but only the things that is absolutely necessary. I believe long load time is to do with unity initializing all the assets involved about the game, my stuff only happens when in the last 15% of the loading bar, and that is quite quick, if i ever figure out how to optimize unity scene load time than i will let you know.