I just tried a 3GB map with 349524 tiles, it loaded it quite nicely and is currently analysing, but I see no memory footprint increase. I spent extra efforts in making sure, that there is no memory leak...
Anyways, for this 3GB map, my memory footprint was around 30MB only... Can you check how much free memory you have? My favourite tool for it is from http://www.prcview.com
Anyways, can you upload your map somewhere, so I can have a look?