i wrote tutorials for fallout 4 and skyrim bringing up some experiences and dependencies regarding performance, modding, setup and stability. my tutorials are buried under the mass of many mods. many questions and mods show that some game engine and interface limitations of open world games, especially the bethesda ones, using dx9 and dx11 interface, are still not common knowledge.
this article is intended to make interested people aware how to understand and handle games like fallout, skyrim and oblivion and their limitations, how to apply thoughtful modding and to lower the risk to accidentally screw up your game. you are invited to help me to correct or add information if something is wrong or missing or to make people more aware.
i managed over time to get all these games - including many mods - to work stable with delivered updates and fixes! so if anyone complains about these games the source is not the game but the way how it is treated and managed.
the bethesda open world since oblivion and fo3 relies on a modified gamebryo engine or framework.
depending on the version there exist bottlenecks especially regarding modern windows related graphics hardware, so called fps drops even with capable hardware based on rendering or draw call bottlenecks.
these bottlenecks or limitations are more and more obvious with the use of higher resolutions, modding or other measures scratching the game engine limits.
you cannot indefinitely raise resolution or the number of mods without reaching a hard limit of the game and graphics interface. if you do so you will encounter fps drops and stutter even with high end hardware if the software interface bottlenecks.
that is the reason why new games are developed with new game engines and for example flight simulators and all new open world games get support for newer interfaces like dx12 or vulkan to reduce the risk of graphics interface related bottlenecks.
the problem is - that will not happen for older games like fallout 4, skyrim, displaying a big and complex open world even more complex enriched with (many) mods. these games will probably always be limited by the dx11 (or dx9) interface, with only minimal support for multithreaded rendering and multithreading at all - which means there will be always a bottleneck between hardware components like cpu and gpu regardless of the core number of a cpu. shfting skyrim from 32bit dx9 to 64bit dx11 is an exception. still graphicswise limited but a huge step to overcome 4GB memory limitation and related stutter and instability. oblivion, fo3 and fnv still suffer from this 32bit limit and an enboost dependency which helps to overcome the 32bit limitation and ctd while introducing stutter even on high end hardware.
with that in mind you can imagine that modding and optimizing a game has its limitations. this is especially true for mod collections, a bundle of mods. just keep that always in mind for people who do not own the newest next gen cpu.
if you like to read some more about open world game specific limitations and the influence of modding check these links and also the links in the tutorials.
thank you for your interest!