Thank you, Thorsten, but you're making the usual developer mistake: you assume I know what the hell you're talking about.
Right... you have 1200 posts to your forum history, so do you really want me to assume you don't know how to use the wiki/ ask if something is unclear?
If there's complex scenery visible, the frame rate plummets. Buildings, objects, vegetation, and shaders are not the cause.
Right again... that makes a lot of sense given that 1) there's mostly ocean in the direction you're looking in the screenshot rather than 'developed' or 'complex' scenery and 2) I have all visual goodies on and get 20 times
less vertices shown on the counter.
It doesn't matter whether I'm in MP or not.
(...)
The only apparent solution is (...) not using multiplayer
I'm sure this makes some sense to you, but to me it makes none whatsoever.
You can't have it both ways - either you want to be the expert who determines the cause of your problems, then spare me the line about not understanding what I'm talking about. Or you let me try to figure out what is happening, then kindly help me get the information I need.
As far as I can see so far, your system seems to exhibit a unique problem which is somewhat different from what I'm seeing and what wlbragg is seeing. So the only avenue to a fix is - you provide information, because I can't reproduce it. This is how these things go. You can delete FG for all I care, it runs fine for me after all - but then don't complain that developers don't fix any bugs if you can't even be bothered to try help tracking down the cause and follow a bunch of simple instructions.
There's one thing I really don't appreciate, and that's me investing my time to try to hunt a bug, and the user who reports it sulking because there isn't a magic fix immediately. Sorry, I'm not clairvoyant, unlike apparently you, I can't know the cause of framerate loss before I have the relevant information.