The traffic alone does not cause issues.
Jorgen, you should not always comment on other peoples posts. On your system, with your addons and other traffic, traffic may at the moment not be the critical point. You have your system but you can't speak for all of us.
You always express your opinion as an unalterable fact. At the moment, we don't know, why my faster system behaves worse with traffic as yours.
Traffic is one point to consider, if all other things did not help. It's not about who is the best expert here, but what experience have others and what can help others. Be happy, you can fly without terrible stutters or crashes.
I have an idea, that maybe the sode setting to attach jetways to ai could make a big difference, if a lot of traffic is set. What is your setting for this? I assume you have SODE, since lot of addons require it.
What about GSX2. Don't you have this installed?