On my harddrive, I created a separate folder called 'Sim Backup' then cut and pasted a heap of aircraft folders that I have installed in my FS9/Aircraft but rarely ever fly (not deleting them permanently in case I wish to fly them again one day, then it is merely as case of coping and pasting them back).
Then I loaded up FS9 and unticked a heap of addon scenery folders that I have installed but rarely fly over, went back to my main FS9 directory and cut the selected folders and pasted them in my new backup folder along with my old aircraft.
It makes my loading time on the first splash screen go by noticeably faster, and also the time from when I go to the ALT menu in flight and select 'change aircraft'. I don't know if it will help you guys with faster machines, but it sure helped me on my 2.4 GHz Celeron


, totaling well over 40gb..