There is a config file that prevents some settings to show up in the ingame graphic options screen for the 32bit version of the game. It is cockpit shadows, textures high, scenes high, civ traffic high, MSAA 8-16 and HDR is forced off.
It's because these settings may cause game stability issues on most 32bit systems.
I have Vista 32 and was kind of disappointed I could not set the textures to high and that HDR was forced off since patch 1.0.0.8 though I always had no problems before.
But now I run the sim with high textures, HDR and cockpit shadows (again), without any serious problems (sometimes during the landing approach I have like a 0.5s lag/stutter! :D)
The only showstopper are scenes set to high.