I havn't noticed many major changes, all I get is a lot of fog.

Change your games video settings. Oblivion auto detects your computers preformance settings for optimole settings ( so your computer doesnt crash) there is a Official plugin that takes a visual setting and gets rid of it because it uses so much of the ram while playing. If you have a low end compture i recommand this. If you have a high end computer turn your video settings up. Other than that you might have to do some trouble shooting or if you have mods installed try seeing which mod is effecting your preformance.

-Naminea