I'm assuming you're using GWX. Stock always loaded pretty quick. Once I got GWX, the load time increased considerably due to the huge increase in units.
My old machine took about 14-16 minutes to load as well, even after doing some RAM changes.
I got a better computer from my wife's work after they upgraded in March/April and now the load times are half of that.
Can't help you on the 1945 thing. I haven't made it that far yet.