If I can run KORD than surely I shouldn't have a problem with KJFK
The area at New York is certainly worse than the Chicago aerea. However, a normal system shouldn't show too much difference, although I have slightly better fps at Chicago, but the difference is small, maybe 2-3 fps, depening on the direction I'm looking at.
I also have the Couatl.exe running multiple times as well. I wonder if this is causing the performance problem?
Another user solved this with a reboot. After a reboot, launch FSX, check that only one Couatl.exe process with the Task Manager. Close FSX and verify that Couatl.exe is closing as well.
However, this wouldn't have any impact on performance, because if two Couatl process are running (it might happen if you close and re-launch FSX too quickly), they would't run twice, but exactly the opposite: none of the two will run instead.
And, it would't have any effect on video perfomances, and certainly not causing antialiasing problems.
Check your AI models: many times we see blame being put on the scenery for crashing or slowing down, and the argument is always that "other sceneries are all fine", only to discover that a specific AI, that has a schedule that brings it only to a certain scenery and not others, had a corrupted, missing, or in the wrong format texture, that might have caused video troubles.