Hi m8.
I have not playd fsx since I built my new rig, the PMDG 737NGX was taking over my life lol so I pulled the plug, maybe when I retire I wil revisit FSX :p
as far as settings go I was using a ati card at the time 6970.
firstly I used Bojotes tweaking tool
http://www.venetubo.com/fsx.html
installed his shader mod 3.0
http://www.venetubo.com/sha3mod.zip
and used fps Limiter
http://www.fsx-online.com/sites/default/files/files/FPS_Limiter_0.2.zip
Unzip the file inside the FSX folder ( "C/ProgramFiles/MicrosoftGames/Microsoft Flight Simulator X" folder) cut the files from the "fpslimiter" folder and past them inside the FSX folder.
click on the "FPS_Limiter_GUI.jar" file, choose D3D9, OGL or D3D8 ( it has something to do with the graphics card i think.)
then search the executable file ( located inside FSX folder, should be " FSX .exe" ), now click on "logging" then " create BAT ".
the ".bat" file has been created inside FSX folder ( should be : FSX.exe.bat or FSX.bat ) click on it, FSX starts and have fun !
hope this helps