Im not saying that i am a god amongst men when it comes to pc, however, i consider myself pretty capable 
But that does not mean that i cant screw something up somewhere.
-
My rig is setup for games… not applications… i dont install stuff i dont need, i dont enable windows features i dont need, i update to stable drivers as they are released, how one sets up a pc for simulation and not gaming is beyond me tbh.
-
Yes, no difference in performance… im also on a 200/200 mBit connection.
-
No i dont. ive tried, but loading back in wether pc is restarted or not gives me the excact same fps.
-
It is in absolutly every condition… Only thing affecting in terms of settings are the TerrainLOD. even in the game`s main menu with no flight loaded or started, terrainLOD affects framerate.
-
Excactly the same as with MP on. i can set the preset to Low end, set renderscale to 30, crank terrainLOD to 200 and still only have 20fps
-
I dont have any addons installed right now… not even liveries or bushtrip/landing challenges or airports where i dont fly locally. just the planes i own with the stock livery
Time will tell when DX12 gets integrated to the sim i guess like fsx dx9 to 10 
Edit:
Doublechecked content manager, 31 installed, 201 not installed. I own the premium deluxe edition