need a button for "physics fps 40 or 50".

[splosions]

It's not a bug (I'm sorry, I don't know where to put this ...)

I have problems with 30 and 60 fps physics. when it is at 30 fps I start to lag inside but on the outside I get more fps.

when the game is 60 fps, i get more fps inside but i lose performance outside.

[AbduSharif]

I'm not sure having physics FPS more than 30 and less than 60 would help as much as this would:

[Physics] async num threads = 2 Change it to more than 2 if you have more than 6 cores.

Physics performance is one big problem with OpenMW itself and hopefully upcoming optimizations (like async physics is already a good step in the right direction) to OpenMW will help with it.

[licaon-kter]

Nightly 43, added that setting but:

 Warning: using custom physics framerate (30 FPS).
Bullet was not compiled with multithreading support, 1 async thread will be used 

[AbduSharif]

Bullet was not compiled with multithreading support, 1 async thread will be used

That's a bullet cmake thing, ask for it, I have it on in my builds.

-DBULLET2_MULTITHREADING=ON

[AbduSharif]

Warning: using custom physics framerate (30 FPS).

This is a harmless warning, just telling about the custom physics FPS you're using (as you can read), because PC uses 60, it's probably there to remind.