So I was wondering if there is significant different between low and Ultra High in Skyrim?

The reason I am checking is cause I can play the game perfectly fine on Ultra High with no Add ons but my game starts crashing at the loading screen with all the add ons I am currently using.

However, when I lower the settings to low the game works perfectly well with all my add ons.

Are there any add ons that conflict with the high settings?

Currently I am using

Enhanced Lighting and FX
Convenient Horses
3D textures.

Then I also have most of the common ones like glowing ore veins, and all.