Hi,
Sorry to bump this old thread up.
I just wanted to explain that I am suffering from exactly the same issue as Ray but instead with Orbx ESSA. I tested my monitor at 1920x1080 and FPS is fine, yet when returning to 3440*1440, my FPS go straight from 30 FPS locked to 6-7 FPS which are making these sceneries unplayable.
I am still researching my issues at EFHK, and cannot reach a conclusion yet. But ESSA is definitely bugged.
I tested dynamic lighting at my native resolution at other airports such as FlyTampa EHAM, Aerosoft EDDF & EGLL, Taxi2Gate LFPG and I do not suffer from this issue there.
Clearly something is wrong with the lighting effects files? It seems to only affect Orbx sceneries (for some reason LYBE is fine, the only exception). If this could be checked and fixed somehow I would be grateful, but otherwise, I would like to apply for a refund as well... The airports are great, but if you can't fly during night (especially winter time it gets dark early), there is no point..