Mission specific lag

[Panthera_Tigris]

Fine tuning settings for optimal performance in VR is quite a task. But I managed to finally strike a good balance for my 1080TI/ Vive combo. Getting 45-90 FPS which is pretty alright with Motion Smoothing.

 

BUT, in some missions that goes down to less than 15 FPS which is intolerable. And I am not talking spikes, it stays below 15 permanently in those missions. For example, the Red Flag Single Mission for the Hornet. Do others also get this level of degradation based on missions (FPS dropping to less than a third)? How do I fix it? What do others do? Just avoid them altogether?