please post comparable examples for your issue which match with the topic “worse performance”, so that we can compare and/or give hints… eg. your system-specs, game-settings, used mods ( where you not should forget that there exist a third-party category ), performance values which are in your opinion worst, etc.
Otherwise about what should we discuss here in this issue-topic ? “degra…of” is just a wide range…
For more generall discussions / rants / whatever we have the blue category, as you allready know: