I have never had to add any special .dll file to play Oblivion, FO3, or NV with my multi-core processor computers. For FO3 and NV all you have to do is put the following two lines in your Fallout.ini
CODE
bUseThreadedAI=1
iNumHWThreads=2
I never even had to do that with Oblivion.
You are not stuck with the game at Medium settings. You can manually set everything to max if you want. In the Launcher just click on the Advanced button, and there are bunch of tabs for different settings. Turn everything up as much as you want.
This post has been edited by SubRosa: Jan 20 2015, 03:44 AM