great amount of free ram and swap file on Ramdisk implies shorter times for loading, but you can't go below 3 sec to load a mission on my rig, it is CPU lmited I suppose : game launched from mapped Ramdisk, no swapfile (500Mo fixed, and less than 20% used), 8 Go still free physical RAM, (test with 24 Go total)
i7-430 @ 4GHz, 24 Go RAM, Sata3 Raptor