Here is a simple safe way to improve FSperformance by telling your CPU to put all it has into running FS. I know this works with Xp but i am unsure about 98 or other windows versions
(I DID NOT invent this, i found it at another site)
1: Browse to your Fs9 install folder using explorer.
2: create a new text file (right click, go to "new", then to "text Document") open this document and place the following inside (no quotes) "start /high fs9.exe"
3:Now go to "file" then "save as" (in the text document) and save the file as (without quotes) "start fs9.bat" you should now see a .bat file that has appeared in your fs9 directory named "start fs9"
4: create a shortcut to start fs9.bat by right clicking the file and clicking "create shortcut" (difficult,i know, but try to bear with me :D ) Now take this shortcut and copy and paste it to your desktop
5: click on this shortcut, and FS9 SHOULD start.
You should now see an improvement in the load times in fs (at minimum) and most people will get FPS improvements and\or smoother gameplay
There is a drawback to this though...as the processor now is mostly working on FS, antyhing else running in the background will slow down or lock up (IE: Roger Wilco, SquakBox or minimized programs like Word or Paint) To avoid the hit on backgroung apps, just load Fs using the normal desktop icon! (use the normal icon for MP flights as well)