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Author FS9.CFG - Care and Maintenance


Posts: 509
Joined: 11.04.06

Posted on 24-12-2006 07:42
KEYWORDS: FS9.CFG | Maintenance | Performance | FSAutoStart


This file, I suspect, is subject to much neglect and abuse by the average end user who cannot resist meddling. Yet, if properly configured and maintained, it can dispel the frustrations endured by the simmer by assuring continued smooth stable operation of our favourite simulator. I preface what I am about to say by stating that this is my own experience gleaned from much trial and error over several months experimentation. Now, the only time I make any changes to FS9.CFG outside the simulator is when I update graphic drivers.

FS9.CFG is vital for the correct operation of FS9, yet it is conceivable that the only time it really integrates fully with the sim is following the moment of initial creation. This initial creation of the contents of the file appears to be executed in a unique way that seems to allow the sim to scan it both quickly and efficiently and, by so doing, allows all the parameter variables to be read and incorporated in the executed code as quickly as possible. Any deviation from this ideal situation quickly leads to file degradation which, in turn, can compromise the sim's performance.

Making changes to FS9.CFG from within the sim is, of course, perfectly okay, but any changes made from outside should be treated with the greatest caution. Not only does the insertion of lines threaten to undermine the ability of the sim to scan FS9.CFG efficiently but repeated overwriting of this file, as changes are saved, can have a similar effect.

Well, if this is true, you may ask, what can I do safely?

What follows is a step-by-step approach which works for me:

1. Run FS9, load your usual startup situation and make a note of ALL your current settings. End Flight and Exit.

2. Backup your current working FS9.CFG (found at C:\Documents and Settings\Your User Name\Application Data\Microsoft\FS9) by making a copy, then delete the original file.

3. Run FS9 and load up the default flight situation at KSEA.

4. Restore ALL your previously noted in sim settings, then End Flight and Exit.

5. OPEN the freshly created FS9.CFG in NOTEPAD and ADD / CHANGE entries as indicated:

(CONTROLS) <----------------N.B. these are Square brackets in FS9.CFG
PAN_RATE=900 <------ very helpful tweak to improve panning in VC and Spot View

UPPER_FRAMERATE_LIMIT=31 (My preferred fps lock)
TEXTURE_BANDWIDTH_MULT=300 <---- Values up to 400 may be tried to improve texture loading times. Too high a value may increase the tendency to stutter on some systems.
RUNWAY_LIGHTS_SURFACE_SCALAR=0.5 <---- My preferred option

TERRAIN_DEFAULT_RADIUS=4.500000 <--- best results on my setup
TERRAIN_EXTENDED_RADIUS=4.500000 <--- ditto

Please don't try to 'tidy' the appearance of the file contents, as existed in FS2002, by creating a space between the various sections. The aim of this exercise is to disturb the original layout as little as possible. Any changes made to the layout should be handled by the sim and NOT forced by the user.

SHOW_BRAKE_MESSAGE=0 <--- optional

Now copy as a block your original Joystick and Keyboard assignments from your FS9.CFG backup file and paste at the bottom of the new FS9.CFG file. This is just a way of sparing you the rigmarole of having to set up these devices again. Should you prefer, you can of course do it from within the sim. However, I have not noted any adverse impact on performance by doing the former.

These are my current headings, yours may differ:

JOYSTICK_MAIN <---- I have rudders

Lastly, I have a couple of additional headings necessary to avoid loading errors. Those familiar with what I mean will understand. If you don't know what I'm referring to AND you are not seeing any errors, then please ignore most of what follows:


If you need these lines to be present, then add them to the bottom of the FS9.CFG file. Don't try inserting them in the main body of the file. FS9 will rearrange their positioning at the next run.

That's about it. What, I hear you say, about all those other tweaks like, for example, PanelAsTexture=0 and TextureAGP=0. I have never used the latter but I have used the former in that it did seem to sharpen up the gauges in the 2D panel noticeably. More recent driver sets from Omega seem to have made this tweak unnecessary and, in any case, I have never really been convinced that there was any useful performance benefit to be gained by including this line.

Okay, so now you have made those minor changes to FS9.CFG without causing any major disturbance to the freshly created construction of the file.

6. Select File - Save As... browse to C:\Documents and Settings\Your User Name\Application Data\Microsoft\FS9 and save the file as FS9a.CFG to avoid overwriting the original.

7. Delete FS9.CFG and Rename FS9a.CFG to FS9.CFG

8. Defragment the drive on which FS is installed to ensure that any file fragments are now contiguous. Not sure whether this is really necessary but does seem to be good practice. Doesn't take long in Windows XP if you are in the habit of doing it regularly.


These are my current driver entries:
(DISPLAY.Device.RADEON 9800 PRO (Omega 2.5.79).0) <---square brackets

It appears it may not be enough to simply install a new driver and load the sim for it to be recognized properly. In this case you are likely to see the appearance of 2 entries in FS9.CFG - the old and the new driver references. Deleting the old reference may disturb FS9's ability to scan the file efficiently so this method is not to be recommended.

Nor is the seemingly attractive ploy of backing up FS9.CFG, deleting the original, creating a new file and then copying and pasting the new driver reference over the old entry in your backup file before saving it as FS9.CFG. What you can try doing, however, is copying and pasting the appropriate lines at the end of FS9.CFG, delete the original lines referring to the old driver, close up the spaces between the remaining entries and allow the sim to reposition the new lines automatically at the next run. That way you know there is a good chance that the sim has accepted these new entries properly.

My preferred method is to rebuild FS9.CFG as detailed above in steps 1 - 8. I know it's a hassle but you do have the reassurance in the knowledge that the sim will have accepted any changes fully. Also the sim's ability to scan the file efficiently will remain unaffected.

If you do feel you still have to make any changes to variable parameter values in FS9.CFG from outside the sim then I suggest you at least get into the habit of saving the file as, say, FS9a.CFG before deleting the original and then rename the freshly saved file to FS9.CFG. Then, throw in a defrag for good measure!


TIP: Flying in areas with differing terrain mesh elevation resolutions presents a problem as it involves opening FS9.CFG to adjust the TERRAIN_MAX_VERTEX_LEVEL (TMVL) to match the LOD of the mesh:

LOD 9 (76m) Mesh requires TERRAIN_MAX_VERTEX_LEVEL=19
LOD 10 (38m) Mesh requires TERRAIN_MAX_VERTEX_LEVEL=20
LOD 11 (19m) Mesh requires TERRAIN_MAX_VERTEX_LEVEL=21

One way to resolve this, and avoid continually having to make changes by overwriting and potentially degrading the original file, is to create 2 additional CFG files with the appropriate adjustment made in each:

fs9_LOD10.CFG (TMVL=20)
fs9_LOD11.CFG (TMVL=21)

Then, all you have to do is rename the original FS9.CFG (with the default TMVL=19), assuming this is the file currently in use, to something like fs9_LOD9.CFG and rename one of the others, as dictated by the mesh LOD, to FS9.CFG in order that it will be recognized by FS9 and go fly.

A better way is to use Ken Salter's excellent FSAutoStart module. This allows the user in the configuration section of each user-defined profile to employ a switch in the Command Line under Application to Launch Options section (for example, "/CFG:fs9_LOD11.cfg" - without the quotes) which effectively calls the correspondingly named FS9_*.CFG configuration file you have placed in the FS9 root folder. smiley
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