Below are the frame rates I'm getting at JFK, system is:
C2D E6700, 2.66 no overclock
8800 GTX no overclock
4GB - Vista 32
Original screens were taken at 1600x1200, 4x FSAA, 16x Anisotropic filtering. They are just resized in Photoshop to post them and slightly sharpened to overcome the jpg compression and make the fps counter readable
MS Default JFK - no AI = 41.0 fpshttp://www.virtualisoftware.com/binaries/images/jfk_fps/kjfk_default_fps1.jpgFSDT JFK - no AI = 33.5 fpshttp://www.virtualisoftware.com/binaries/images/jfk_fps/fsdt_jfk_fps1.jpgAerosoft EGLL - no AI = 26.2 fpshttp://www.virtualisoftware.com/binaries/images/jfk_fps/egll_fps.jpgObviously, no settings were changed, just switch locations.
This is the scenery impact comparing to default and to a similarly complex scenery like EGLL. Testing without AI it's the only way to compare different sceneries, because otherwise you'll end up comparing the AI models impact.
However, I've put some screenshots with AI as well:
FSDT JFK with AI at 50% = 20.3 fpshttp://www.virtualisoftware.com/binaries/images/jfk_fps/jfk_fps_50ai.jpgFSDT JFK with AI at 100% = 13.1 fpshttp://www.virtualisoftware.com/binaries/images/jfk_fps/jfk_fps_100ai.jpgSo, the only thing that can really slow down the sim are the AI, not the scenery.
Note, that at JFK we HAVE airplane shadows turned ON. Unfortunately, we can't compare it with EGLL, because that one doesn't supports airplane shadows with FS9 AI models (a problem we had in Zurich but not in KORD/JFK), so I had to turn airplane shadows off to see AI at EGLL
Aerosoft EGLL with 50% AI - shadows off = 17.0 fpshttp://www.virtualisoftware.com/binaries/images/jfk_fps/egll_50ai_noshadows.jpgAerosoft EGLL with 100% AI - shadows off = 12.7 fpshttp://www.virtualisoftware.com/binaries/images/jfk_fps/egll_fps_100ai_noshadows.jpgOf course, if we turn shadows off at JFK, we get better fps:
FSDT JFK with AI at 50% . shadows off = 23.0 fpshttp://www.virtualisoftware.com/binaries/images/jfk_fps/jfk_fps_50ai_noshadows.jpgFSDT JFK with AI at 100% . shadows off = 18.6 fpshttp://www.virtualisoftware.com/binaries/images/jfk_fps/jfk_fps_100ai_noshadows.jpgSo, this should clarify how the scenery should perform on a machine very similar to yours and how it compares to a similarly complex scenery like EGLL.
Now, it's impossible to understand why it doens't run well on YOUR machine, without knowing anything of your settings and what other addons you have, what airplane you use, etc. However, with everything else being equal, it's clear that JFK it's faster then EGLL.