I can't understand , I have both simulators; I USE BOTH SIMULATORS FS9 & FSXAcceleration in a single 80gb HDD I still have 40Gb of free space ,why to make this so complicated? :-/
Jeezz!! I just souds as Avril Lavigne ;D
Every game its unique FSX in impressive ,although FS9 the cities are much more realistic than FSX
Both are great FS204 still need more years to leave us ,Not like FS2002
I purchased FSX on the day it was released, and very soon found out that it was very inferior to my existing FS 2004 when forced to reduce all the FSX settings to obtain satisfactory Frame Rates and smoothness!
I still have it installed on my hard drive but never use it, as I have no wish to be associated with the FSX Forum when having to discuss the FSX Sim...

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...I have this image of a "Pit of Vipers" each time I consider it...

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(I've watched it closely from day one!)
So its FS 2004 for me all the way, until the day arrives when I can run it with suitable Hardware, and M$ have finally got all the FSX problems fixed, so that I have no need to visit the FSX Forum..

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F....FS 2004....with a smile... 8-)...!