Heres one that you might not know. FS9 unlike FS2002 has the ability to set the optimum frame rates for your system. There is no need to lock the rates.

Unlike FS2002, which will at all costs attempt to reach the locked rate thus using valuable memory and CPU time, FS9 will only achieve what it can....... So unlock the framerates and try it .

I have ........ it works .. at times the rates are over 20, on the system specs below, most of the time they tick over at 10-15, they only drop off at large airports with heavy traffic.

cheers
eno