SureAI

Finally after innumerable CTD-s and Game freezes which made the Game almost unplayable, I discovered the problem. I started comparing the original oblivion_default.ini file and the nehrim_default.ini file because I started to suspect the Nehrim Launcher for my problems. Since I could play my original Oblivion Game without any problems whatsoever, I figured that the nehrim_default.ini file created by the Nehrim Launcher causes the crashes.
The solution: first remove the nehrim_default.ini file in your game directory by remaming it nehrim_default.old. Now move a copy of your oblivion_default.ini file from your original Oblivion folder - you did remember to make a copy of Oblivion before installing Nehrim I hope !!! - and simply rename it nehrim_default.ini .
After this change I have played Nehrim smoothly without any crashes or freezes for hours. As I mentioned I am playing the Steam version on Windows 7, but I am pretty sure that it would work with any version.
The comparison of the ini files showed that the one created by Nehrim Launcher is full of unnecessary parameter statements which will eventually drag the Game down.

Uhh, nice! I will try that some time and see if it improves my games performance as well. Its running, but it wouldnt manage to run 3 hrs nonstop.

Well ty for the solution , it worket for me at least until now, i ve played 3 hours with crush-free

....unfortunatly , after some more hours of play i ve encountered the same problems

Maybe you can forward the stuff about unnecessary parameter statements to the team anyway, it could perhaps help others if they removed them.

To Daniel.
Sorry for the late reply but these days I dont have time for my Computer.
Anyway, I found that the crashes and freezes were caused by a catastrophic memory leak problem. Using the Task Manager I checked the size of Oblivion.exe in memory at the beginning of a game session: it was around 600 kbyte. When the game froze I quickly checked again and it was 1.600 kbytes rapidly increasing to over 1.7 kbyte when it crashed.
This made me think about the settings and next I compared the original Oblivion.ini file with the Nehrim.ini file and found that the Nehrim.ini file was much larger the the Oblivion.ini file. Then using a file comparison utility program I compaired the two ini files line by line and found large blocks of definitions in the Nehrim.ini file which did not appear in the original Oblivion.ini file. I did not have the time go into details about these but your team could duplicate my experiment and look into it deeper.
In my experience switching to the original Oblivion.ini file worked well I could play for hours without a hitch. As long as you do not use the Nehrim launcher this will work, keep in mind that the Nehrim launcher will create a new ini file if you make even minimum changes in it.
But the major problem is a memory leak without any question.

Did you use some of the optimizations in the luancher?

To arvisrend:
Yes I did in the beginning, but when I started to realize the problems and changed my ini files, I NEVER used the nehrim launcher again, I always started the Game through the Oblivion launcher from Steam.
Actualy the original oblivion Game used to have memory leak problems but Obsidian rectified this with a patch. There is a "Oblivion Tweek Guide" on the Internet which details which instructions cause memory leak problems.

What tweak guide are you talking about?
And Obsidian??

To arvisrend,

These are some of the tweakguides I was referring to:

http://www.tweakguides.com/Oblivion_1.html

http://www.uesp.net/wiki/Oblivion:Ini_Settings

Of course "Obsidian" was a mistake, I was in a hurry, too much "Oblivion" must have confused my mind. It is Bethesda. We all make mistakes !