Framedrops in Budapest

[777-Pilot]

Hi,

I am having a weird issue with Budapest (in P3D V4.4): When taxiing on a certain part of the taxiway, my framerate drops from about 25-30 FPS to 15-20. This seems to happen at a certain "line" in the scenery. When crossing it my framerate drops (or goes back to normal) dependant on what side I am. Here are two videos  to see for yourself:

https://youtu.be/2Eae3d5Sq4o
https://youtu.be/2nObFT0vpRM

Any idea what could cause this? To be fair; I have very similar issues in other sceneries like in Aerosofts Heathrow - so maybe this is a problem with my sim?