AI Traffic: FPS when moving

Hey guys,

I've done the massive migration from FS9 to FSX once I realized that my frames wern't that bad. Here's my one problem though:

I can be sitting on the runway looking at an airport like Flightbeam KIAD or KLAX, with AI planes parked at the gate, and there's no performance problem. However, when looking directly at aircraft that are moving, like for example at a lineup at a runway, with 3-4 planes taking off, my FPS drops sharply (and this isn't with the airport buildings in sight anymore).

I remember AI traffic being a bit heavy in FS9, but I can't remember AI planes in movement having this much of an effect on FPS. It seems to be the only thing dragging my FPS down. I should add that I am using UT2 AI traffic.

Does anyone know what might be causing this? I'm out of ideas.

Thanks,

J