hi
you can try the free version of Ramdisk and "mklink" some of your FSX folders to the Ram-Memory, it helped me alot. link to a tutorial (sorry i only know this german one, maybe you can use googletranslate) http://www.forum.eulenandfriends.de/index.php/Thread/10856-FSX-oder-P3D-mit-RAM-Disk/
i had no CTD's since i setup this... running same fsx-install since 2 years, and errors are very very rare. (but im still fighting whit the FPS in FSX... whit the NGX i reach at least 24fps when im lucky, around 20fps is the centerline...)
folders i "mklink" :
Animals
Autogen
Boats
Effects
Gauges
GroundVehicles
Misc
Texture
Weather