not ultimate traffic, ultimate terrain x
Doesn't matter, if you have busy/real world schedules, the quantity would be as high as Ultimate Traffic
also i only use modeles from evai, woai, tfs, aia, etc
Doesn't matter, since there are no FSX native version for these models. These were good choices in FS9. Or, better yet, these were *mandatory* choices in FS9, for an airport THIS size, especially with a real world schedule, and KORD is one of the busiest airports in the world.
In FSX, you really can't expect a performance level from these FS9 models, both because of the sheer *number* of AI you can see at KORD with 100% density, and BOTH because you are trying to use FS9 models in FSX and anything done for FS9 IS slower in FSX, because is using a different rendering path for the backward compatibility.
Or, better yet, try the KORD AFCAD over the *default* KORD scenery with AI at 100%. You will probably have similarly bad fps. You really can't expect an addon scenery to auto-magically speed up the rendering of 300+ AI airplanes, something that no PC can really do, even when there's no scenery.
With such number, just the AI textures alone (without even start counting the scenery, the landclass, weather, clouds, the user airplane, the VC textures, etc) will be able to fill up your VRAM. Once textures don't fit in VRAM anymore, performance will dramatically drop.
I repeat and confirm: your 3 fps figure is entirely due to the AI. As I've said, try with AI at 0%, and see what's happening.