i have heard that if you change the name of the fsx file :default.xml to defaultbak.xml that the framerates should go up.any one who knows a little more about this statement?

I believe the effect of deleting or renaming default.xml is that some types of autogen do not get loaded. So that would probably improve FPS.Why not just try it?

i will try it as soon as i know a little more.what type of autogen doesnot load? is it specific trees or buildings are librairy stuf.i cannot find the deault xml.i know the path app/ms/fsx but than i dont see this

Good Day,In FS9 when renaming the default.xml to a backup name, a nice FPS increase was gained with minimal impact on visuals for me. I kept in renamed for many years. When renamed in FSX I lost most of my autogen scenery, almost all the trees and the FPS increase was not worth big loss of visual detail.In any case the file can be found in your main Flight Simulator X/Autogen Folder if you want to give it a try.......... JayDub

ok thanksbut why do they choose for this renamingis it not easier to move the slider of autogen trees to zero?

There is no separate control for trees under the autogen settings.......... Try this for a good balance, and possible performance increase for your system.Under [TERRAIN] in your fsx.cfg file add the following lines.......[TERRAIN]TERRAIN_MAX_AUTOGEN_TREES_PER_CELL=1000TERRAIN_MAX_AUTOGEN_BUILDINGS_PER_CELL=500Some may think this is a low setting but I find it is a great balance between performance and visuals, I have all the other settings in scencery set at MAX except water which is at low 2.x with FPS locked at 31 in the sim ....... I fly mainly in Orbx sceneries and it does very well in all of their North Amercian areas with good FPS and smoothness and these areas are very high in tree autogen........ If you can't find your fsx.cfg file check the forums search for the location as depends on your operating system...... Let me know how this works for you........Good Luck,JayDub

In FS9, there was a bug/memory leak that caused the few special objects called from the default.xml file to decrease the frame rate dramatically. Renaming or deleting the file caused a huge FPS increase for some, while having a minimal impact on scenery quality (you lost a few light poles, barns and fast food restaurants). This was partially (but not completely) fixed in the FS9.1 update.In FSX however, the underlying bug/memory leak has been fixed. Also, many more objects appear to be called from the default.xml file, so the visual impact of altering the file is greater. There are more effective autogen tweaks for this sim, such as the one pointed out by Jay. That tweak is even officially documented by Microsoft:http://support.microsoft.com/kb/555739

Wasn't that some rather old and faulty performance tip from the first days of FSX?Since quite some devs use the default.xml to define their custom placement of autogen, you may gain performance but lose a lot of nice detail. So if you are looking for more fps, lowering the autogen slider helps more than the disabled files. At least it keeps the file structure intact.I think some scenery dev can say more about this. The placement (Apart from the default one) via the default.xml isn't really a standard thing, but some devs seemed to have worked around some FSX limitations there, so the thing is needed, not only for the default autogen.E. g. FlyTampa modifies some stuff there, Orbx does too but exchanges the file in whole when switching on the FTX mode. Other examples are France VFR or Earth Simulations I think.So I'd say that on a fairly modern system, this rough disabling technique isn't worth recommending.