still don't know why users are so  obsessed with their fps

IMO trying to achieve 50-60+fps would be obsessing, trying to keep it 20-30 is just making sure you have some breathing space and keeping it closer to motion than a slide show. For me anything under 20fps starts to feel choppy. All of my experience is from FSX though, where it can just randomly go to 5 fps right when you need to start the flare. But if this doesn't happen in P3D maybe you don't need the headroom. Is that what people mean when they refer to smoothness? And therefore you don't need the breathing space?

In P3D I have lower FPS, but more stable, I mean FPS are constantly between 27-28 FPS, there is less dispersion, not like FSX where i can get 20- 32 FPS