I see in a lot of places that on FSX Windows 7 we should not enable preview Direct X10.
That's of course wrong, and doesn't make any sense, since DX10 is not even possible on XP, for example.
GSX is 100% compatible with DX10 without any fixes BUT, it's possible that your video drivers have a problem in DX10 if you run FSX in "Compatibility" mode. THIS (the compatibility mode) shouldn't be used together with DX10 and, in fact, shouldn't be used at all with FSX.
So, if you have any of the Compatibility modes active with FSX; turn them off entirely, because this will cause visual problems with objects.
If that doesn't work, try all the following:
- Update your video driver
- Reset your video driver settings to default
- Reset the FSX settings to default, by removing the following file:
%APPDATA%\Microsof\FSX\FSX.CFG
This will force FSX to rebuild a new config with all default settings. After doing this, be sure you apply the HIGHMEMFIX tweak in the Addon Manager, save the settings and restart FSX.