First of all let me clarify that this not a VAS issue, I have absolutely no problem with VAS and I have read the relevant thread but could not find anything relevant.
I am using P3D v3.4 HF2 and the other relevant addons in the area are FTX Global NG Ultimate, FTX Global, Vector and Orbx Germany North. I have the options trimmed to my system capabilities and personal flying style to get a smooth flying experience without any VAS or fps issues, especially since I like long haul flights. Therefore after a lot of testing I believe I have a balanced system, sacrificing looks for performance where needed. This is a clean system in a partition dedicated for FS without any non-FS related software to avoid unnecessary conflicts. Finally there is absolutely no pirated software in my FS partition (yes I am one of those few who buy everything they use..).
Having said that, let me explain what I am facing. Yesterday I decided to make a trip to Frankfurt since I had the scenery for some time but never got around to try it out. Usually before going to a freshly installed airport with a descent aircraft I pay it a visit with a default one, either the piper cub or the F22 to make sure everything is ok. Loaded the F22 on the runway threshold for a quick test run. Initially I was getting 30 fps (locked) when I noticed that every few seconds when I was moving only the fps would drop to 5 then back to 30 creating an unflyable experience. The free VAS at the time was ~2GB. I checked my hardware monitor and noticed that the GPU, an Asus ROG Strix GeForce® GTX 1080 OC edition 8GB, was spiking every few second when I was trying to move at an around the airport. My first step was to disable Germany North and Vector to see if that was the culprit but no luck. Then I disabled the airport only and everything went back to silky smooth. There was no weather used during the testing. Usually when I fly to a "heavy" area like London or New York or Los Angeles I do experience a drop in fps to ~20 but the movement is smooth despite that with constant fps. For some strange reason in Frankfurt the GPU is spiking every few seconds resulting in momentary fps drops and subsequent hangs in the sim. It seems that the airport is the culprit. Anyone else that has faced a similar situation and found the cause for it? I have a complete collection of German Airports (and a lot of other payware airports for that matter) but this is the first time I am facing something like this..