I would be most interested to learn more details about what you did here, so I can modify my own Streamline setup.
Here's what I did:
Edit Oblivion.ini and set:
uGridDistantTreeRange=15uGridDistantCount=15
This makes all distant trees and other objects (made visible by RAEVWD) disappear at ranges above 15 cells. This will do a lot for your framerate when using RAEVWD.
Then, in Streamline's sl.ini I use:
set SLv.MinDistanceFog to 20000; Min distance before fog starts (0%)set SLv.MaxDistanceFog to 86000; Max distance before fog ends (100%)
in order to make the fog appear around the same distance.
The net result is better framerates since the engine doesn't have to generate so many distant objects, and more immersive gameplay as the fog not only hides the pop-up of those distant objects, but also makes the world seem bigger when you no longer can see directly from one city to another since the distant lands are covered by fog.
For even better performance, you could reduce the distances even further. If you change the distant settings to 12 (cells), you must set the fog to 17000/71000 instead, etc. The corresponding values are found in the file "Streamsight Fog Ranges.mht" that comes with the Streamline docs
Also make sure to re-initialize Streamline, as it only reads its own ini file after re-initialization.
For the record, I use the following features of Streamline:
1. The fog (obviously)
2. Manual streamsaves (I have turned off all automatic saves, and relies on manual Streamsaves most of the time)
3. Purging before each save.