Found this on Avsim
Good framerates and nice scenery views require modification of the FS9.CFG file. Here is an improved FS9.CFG file with READ ME full of explanations and hints. Want sharp outside world-views and good framerates - then try this one!
link ➡
make a back-up of your orignal CFG first tho!!. Replace it with the new one start up FS9 and you want be sorry trust me.
Let me know what you think after you have tried it.
Liono
Chief Captain
First Officer